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5853fe790d
3306 zdb should be able to issue reads in parallel
3321 'zpool reopen' command should be documented in the man
page and help
Reviewed by: Adam Leventhal <ahl@delphix.com>
Reviewed by: Matt Ahrens <matthew.ahrens@delphix.com>
Reviewed by: Christopher Siden <chris.siden@delphix.com>
Approved by: Garrett D'Amore <garrett@damore.org>
References:
illumos/illumos-gate@31d7e8fa33
https://www.illumos.org/issues/3306
https://www.illumos.org/issues/3321
The vdev_file.c implementation in this patch diverges significantly
from the upstream version. For consistenty with the vdev_disk.c
code the upstream version leverages the Illumos bio interfaces.
This makes sense for Illumos but not for ZoL for two reasons.
1) The vdev_disk.c code in ZoL has been rewritten to use the
Linux block device interfaces which differ significantly
from those in Illumos. Therefore, updating the vdev_file.c
to use the Illumos interfaces doesn't get you consistency
with vdev_disk.c.
2) Using the upstream patch as is would requiring implementing
compatibility code for those Solaris block device interfaces
in user and kernel space. That additional complexity could
lead to confusion and doesn't buy us anything.
For these reasons I've opted to simply move the existing vn_rdwr()
as is in to the taskq function. This has the advantage of being
low risk and easy to understand. Moving the vn_rdwr() function
in to its own taskq thread also neatly avoids the possibility of
a stack overflow.
Finally, because of the additional work which is being handled by
the free taskq the number of threads has been increased. The
thread count under Illumos defaults to 100 but was decreased to 2
in commit 08d08e due to contention. We increase it to 8 until
the contention can be address by porting Illumos #3581.
Ported-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #1354
499 lines
9.4 KiB
Groff
499 lines
9.4 KiB
Groff
'\" t
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.\"
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.\" This file and its contents are supplied under the terms of the
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.\" Common Development and Distribution License ("CDDL"), version 1.0.
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.\" You may only use this file in accordance with the terms of version
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.\" 1.0 of the CDDL.
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.\"
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.\" A full copy of the text of the CDDL should have accompanied this
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.\" source. A copy of the CDDL is also available via the Internet at
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.\" http://www.illumos.org/license/CDDL.
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.\"
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.\"
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.\" Copyright 2012, Richard Lowe.
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.\" Copyright (c) 2012 by Delphix. All rights reserved.
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.\"
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.TH "ZDB" "8" "February 15, 2012" "" ""
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.SH "NAME"
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\fBzdb\fR - Display zpool debugging and consistency information
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.SH "SYNOPSIS"
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\fBzdb\fR [-CumdibcsDvhLXFPA] [-e [-p \fIpath\fR...]] [-t \fItxg\fR]
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[-U \fIcache\fR] [-M \fIinflight I/Os\fR] [\fIpoolname\fR
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[\fIobject\fR ...]]
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.P
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\fBzdb\fR [-divPA] [-e [-p \fIpath\fR...]] [-U \fIcache\fR]
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\fIdataset\fR [\fIobject\fR ...]
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.P
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\fBzdb\fR -m [-LXFPA] [-t \fItxg\fR] [-e [-p \fIpath\fR...]] [-U \fIcache\fR]
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\fIpoolname\fR [\fIvdev\fR [\fImetaslab\fR ...]]
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.P
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\fBzdb\fR -R [-A] [-e [-p \fIpath\fR...]] [-U \fIcache\fR] \fIpoolname\fR
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\fIvdev\fR:\fIoffset\fR:\fIsize\fR[:\fIflags\fR]
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.P
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\fBzdb\fR -S [-AP] [-e [-p \fIpath\fR...]] [-U \fIcache\fR] \fIpoolname\fR
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.P
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\fBzdb\fR -l [-uA] \fIdevice\fR
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.P
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\fBzdb\fR -C [-A] [-U \fIcache\fR]
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.SH "DESCRIPTION"
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The \fBzdb\fR utility displays information about a ZFS pool useful for
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debugging and performs some amount of consistency checking. It is a not a
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general purpose tool and options (and facilities) may change. This is neither
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a fsck(8) nor an fsdb(8) utility.
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.P
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The output of this command in general reflects the on-disk structure of a ZFS
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pool, and is inherently unstable. The precise output of most invocations is
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not documented, a knowledge of ZFS internals is assumed.
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.P
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When operating on an imported and active pool it is possible, though unlikely,
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that zdb may interpret inconsistent pool data and behave erratically.
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.SH "OPTIONS"
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Display options:
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.sp
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.ne 2
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.na
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\fB-b\fR
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.ad
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.sp .6
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.RS 4n
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Display statistics regarding the number, size (logical, physical and
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allocated) and deduplication of blocks.
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.RE
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.sp
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.ne 2
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.na
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\fB-c\fR
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.ad
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.sp .6
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.RS 4n
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Verify the checksum of all metadata blocks while printing block statistics
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(see \fB-b\fR).
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.sp
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If specified multiple times, verify the checksums of all blocks.
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.RE
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.sp
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.ne 2
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.na
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\fB-C\fR
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.ad
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.sp .6
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.RS 4n
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Display information about the configuration. If specified with no other
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options, instead display information about the cache file
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(\fB/etc/zfs/zpool.cache\fR). To specify the cache file to display, see
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\fB-U\fR.
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.P
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If specified multiple times, and a pool name is also specified display both
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the cached configuration and the on-disk configuration. If specified multiple
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times with \fB-e\fR also display the configuration that would be used were the
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pool to be imported.
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.RE
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.sp
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.ne 2
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.na
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\fB-d\fR
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.ad
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.sp .6
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.RS 4n
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Display information about datasets. Specified once, displays basic dataset
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information: ID, create transaction, size, and object count.
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.sp
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If specified multiple times provides greater and greater verbosity.
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.sp
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If object IDs are specified, display information about those specific objects only.
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.RE
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.sp
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.ne 2
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.na
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\fB-D\fR
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.ad
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.sp .6
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.RS 4n
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Display deduplication statistics, including the deduplication ratio (dedup),
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compression ratio (compress), inflation due to the zfs copies property
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(copies), and an overall effective ratio (dedup * compress / copies).
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.sp
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If specified twice, display a histogram of deduplication statistics, showing
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the allocated (physically present on disk) and referenced (logically
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referenced in the pool) block counts and sizes by reference count.
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.RE
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.sp
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.ne 2
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.na
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\fB-h\fR
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.ad
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.sp .6
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.RS 4n
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Display pool history similar to \fBzpool history\fR, but include internal
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changes, transaction, and dataset information.
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.RE
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.sp
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.ne 2
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.na
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\fB-i\fR
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.ad
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.sp .6
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.RS 4n
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Display information about intent log (ZIL) entries relating to each
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dataset. If specified multiple times, display counts of each intent log
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transaction type.
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.RE
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.sp
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.ne 2
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.na
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\fB-l\fR \fIdevice\fR
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.ad
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.sp .6
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.RS 4n
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Display the vdev labels from the specified device. If the \fB-u\fR option is
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also specified, also display the uberblocks on this device.
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.RE
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.sp
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.ne 2
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.na
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\fB-L\fR
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.ad
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.sp .6
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.RS 4n
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Disable leak tracing and the loading of space maps. By default, \fBzdb\fR
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verifies that all non-free blocks are referenced, which can be very expensive.
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.RE
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.sp
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.ne 2
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.na
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\fB-m\fR
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.ad
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.sp .6
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.RS 4n
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Display the offset, spacemap, and free space of each metaslab.
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When specified twice, also display information about the maximum contiguous
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free space and the percentage of free space in each space map. When specified
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three times display every spacemap record.
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.RE
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.sp
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.ne 2
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.na
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\fB-R\fR \fIpoolname\fR \fIvdev\fR:\fIoffset\fR:\fIsize\fR[:\fIflags\fR]
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.ad
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.sp .6
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.RS 4n
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Read and display a block from the specified device. By default the block is
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displayed as a hex dump, but see the description of the \'r\' flag, below.
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.sp
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The block is specified in terms of a colon-separated tuple \fIvdev\fR (an
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integer vdev identifier) \fIoffset\fR (the offset within the vdev) \fIsize\fR
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(the size of the block to read) and, optionally, \fIflags\fR (a set of flags,
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described below).
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.sp
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.ne 2
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.na
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\fBb\fR \fIoffset\fR
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.ad
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.sp .6
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.RS 4n
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Print block pointer
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.RE
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.sp
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.ne 2
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.na
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\fBd\fR
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.ad
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.sp .6
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.RS 4n
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Decompress the block
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.RE
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.sp
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.ne 2
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.na
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\fBe\fR
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.ad
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.sp .6
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.RS 4n
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Byte swap the block
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.RE
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.sp
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.ne 2
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.na
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\fBg\fR
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.ad
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.sp .6
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.RS 4n
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Dump gang block header
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.RE
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.sp
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.ne 2
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.na
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\fBi\fR
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.ad
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.sp .6
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.RS 4n
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Dump indirect block
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.RE
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.sp
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.ne 2
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.na
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\fBr\fR
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.ad
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.sp .6
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.RS 4n
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Dump raw uninterpreted block data
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.RE
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.RE
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.sp
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.ne 2
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.na
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\fB-s\fR
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.ad
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.sp .6
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.RS 4n
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Report statistics on \fBzdb\fR\'s I/O. Display operation counts, bandwidth,
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and error counts of I/O to the pool from \fBzdb\fR.
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.RE
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.sp
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.ne 2
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.na
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\fB-S\fR
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.ad
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.sp .6
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.RS 4n
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Simulate the effects of deduplication, constructing a DDT and then display
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that DDT as with \fB-DD\fR.
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.RE
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.sp
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.ne 2
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.na
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\fB-u\fR
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.ad
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.sp .6
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.RS 4n
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Display the current uberblock.
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.RE
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.P
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Other options:
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.sp
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.ne 2
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.na
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\fB-A\fR
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.ad
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.sp .6
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.RS 4n
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Do not abort should any assertion fail.
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.RE
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.sp
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.ne 2
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.na
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\fB-AA\fR
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.ad
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.sp .6
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.RS 4n
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Enable panic recovery, certain errors which would otherwise be fatal are
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demoted to warnings.
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.RE
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.sp
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.ne 2
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.na
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\fB-AAA\fR
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.ad
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.sp .6
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.RS 4n
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Do not abort if asserts fail and also enable panic recovery.
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.RE
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.sp
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.ne 2
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.na
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\fB-e\fR [-p \fIpath\fR]...
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.ad
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.sp .6
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.RS 4n
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Operate on an exported pool, not present in \fB/etc/zfs/zpool.cache\fR. The
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\fB-p\fR flag specifies the path under which devices are to be searched.
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.RE
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.sp
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.ne 2
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.na
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\fB-F\fR
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.ad
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.sp .6
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.RS 4n
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Attempt to make an unreadable pool readable by trying progressively older
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transactions.
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.RE
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.sp
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.ne 2
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.na
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\fB-M \fIinflight I/Os\fR \fR
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.ad
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.sp .6
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.RS 4n
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Limit the number of outstanding checksum I/Os to the specified value. The
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default value is 200. This option affects the performance of the \fB-c\fR
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option.
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.RE
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.sp
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.ne 2
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.na
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\fB-P\fR
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.ad
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.sp .6
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.RS 4n
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Print numbers in an unscaled form more amenable to parsing, eg. 1000000 rather
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than 1M.
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.RE
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.sp
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.ne 2
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.na
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\fB-t\fR \fItransaction\fR
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.ad
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.sp .6
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.RS 4n
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Specify the highest transaction to use when searching for uberblocks. See also
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the \fB-u\fR and \fB-l\fR options for a means to see the available uberblocks
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and their associated transaction numbers.
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.RE
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.sp
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.ne 2
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.na
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\fB-U\fR \fIcachefile\fR
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.ad
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.sp .6
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.RS 4n
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Use a cache file other than \fB/etc/zfs/zpool.cache\fR.
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.RE
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.sp
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.ne 2
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.na
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\fB-v\fR
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.ad
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.sp .6
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.RS 4n
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Enable verbosity. Specify multiple times for increased verbosity.
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.RE
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.sp
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.ne 2
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.na
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\fB-X\fR
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.ad
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.sp .6
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.RS 4n
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Attempt \'extreme\' transaction rewind, that is attempt the same recovery as
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\fB-F\fR but read transactions otherwise deemed too old.
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.RE
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.P
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Specifying a display option more than once enables verbosity for only that
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option, with more occurrences enabling more verbosity.
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.P
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If no options are specified, all information about the named pool will be
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displayed at default verbosity.
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.SH "EXAMPLES"
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.LP
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\fBExample 1 \fRDisplay the configuration of imported pool 'rpool'
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.sp
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.in +2
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.nf
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# zdb -C rpool
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MOS Configuration:
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version: 28
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name: 'rpool'
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...
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.fi
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.in -2
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.sp
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.LP
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\fBExample 2 \fRDisplay basic dataset information about 'rpool'
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.sp
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.in +2
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.nf
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# zdb -d rpool
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Dataset mos [META], ID 0, cr_txg 4, 26.9M, 1051 objects
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Dataset rpool/swap [ZVOL], ID 59, cr_txg 356, 486M, 2 objects
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...
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.fi
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.in -2
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.sp
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.LP
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\fBExample 3 \fRDisplay basic information about object 0
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in 'rpool/export/home'
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.sp
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.in +2
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.nf
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# zdb -d rpool/export/home 0
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Dataset rpool/export/home [ZPL], ID 137, cr_txg 1546, 32K, 8 objects
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Object lvl iblk dblk dsize lsize %full type
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0 7 16K 16K 15.0K 16K 25.00 DMU dnode
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.fi
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.in -2
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.sp
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.LP
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\fBExample 4 \fRDisplay the predicted effect of enabling deduplication on 'rpool'
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.sp
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.in +2
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.nf
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# zdb -S rpool
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Simulated DDT histogram:
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bucket allocated referenced
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______ ______________________________ ______________________________
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refcnt blocks LSIZE PSIZE DSIZE blocks LSIZE PSIZE DSIZE
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------ ------ ----- ----- ----- ------ ----- ----- -----
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1 694K 27.1G 15.0G 15.0G 694K 27.1G 15.0G 15.0G
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2 35.0K 1.33G 699M 699M 74.7K 2.79G 1.45G 1.45G
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...
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dedup = 1.11, compress = 1.80, copies = 1.00, dedup * compress / copies = 2.00
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.fi
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.in -2
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.sp
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.SH "SEE ALSO"
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|
zfs(8), zpool(8)
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