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18 Commits
Author | SHA1 | Message | Date | |
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Brian Behlendorf
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64bdf63f5c
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ztest: split block reconstruction
Increase the default allowed number of reconstruction attempts. There's not an exact right number for this setting. It needs to be set large enough to cover any realistic failure scenarios and small enough to avoid stalling the IO pipeline and invoking the dead man detection. The current value of 256 was empirically determined to be too low based on multi-day runs of ztest. The fault injection code would inject more damage than could be reconstructed given the relatively small number of attempts. However, in all observed cases the block could be reconstructed using a slightly higher limit. Based on local testing increasing the default value to 4096 was determined to strike the best balance. Checking all combinations takes less than 10s in the worst case, and has so far eliminated the vast majority of false positives detected by ztest. This delay is roughly on par with how long retries may be performed to a misbehaving HDD and was deemed to be reasonable. Better to err on the side of a brief delay rather than fail to reconstruct the data. Lastly, the -Y flag has been added to zdb to make it easy to try all possible combinations when performing split block reconstruction. For badly damaged blocks with 18 splits, they can be fully enumerated within a few minutes. This has been done to ensure permanent errors are never incorrectly reported when ztest verifies the pool with zdb. Reviewed by: Tom Caputi <tcaputi@datto.com> Reviewed by: Matt Ahrens <mahrens@delphix.com> Reviewed by: Serapheim Dimitropoulos <serapheim@delphix.com> Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Closes #8271 |
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Serapheim Dimitropoulos
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61c3391acc |
Serialize ZTHR operations to eliminate races
Adds a new lock for serializing operations on zthrs. The commit also includes some code cleanup and refactoring. Reviewed by: Matt Ahrens <mahrens@delphix.com> Reviewed by: Tom Caputi <tcaputi@datto.com> Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Serapheim Dimitropoulos <serapheim@delphix.com> Closes #8229 |
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George Wilson
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619f097693 |
OpenZFS 9102 - zfs should be able to initialize storage devices
PROBLEM ======== The first access to a block incurs a performance penalty on some platforms (e.g. AWS's EBS, VMware VMDKs). Therefore we recommend that volumes are "thick provisioned", where supported by the platform (VMware). This can create a large delay in getting a new virtual machines up and running (or adding storage to an existing Engine). If the thick provision step is omitted, write performance will be suboptimal until all blocks on the LUN have been written. SOLUTION ========= This feature introduces a way to 'initialize' the disks at install or in the background to make sure we don't incur this first read penalty. When an entire LUN is added to ZFS, we make all space available immediately, and allow ZFS to find unallocated space and zero it out. This works with concurrent writes to arbitrary offsets, ensuring that we don't zero out something that has been (or is in the middle of being) written. This scheme can also be applied to existing pools (affecting only free regions on the vdev). Detailed design: - new subcommand:zpool initialize [-cs] <pool> [<vdev> ...] - start, suspend, or cancel initialization - Creates new open-context thread for each vdev - Thread iterates through all metaslabs in this vdev - Each metaslab: - select a metaslab - load the metaslab - mark the metaslab as being zeroed - walk all free ranges within that metaslab and translate them to ranges on the leaf vdev - issue a "zeroing" I/O on the leaf vdev that corresponds to a free range on the metaslab we're working on - continue until all free ranges for this metaslab have been "zeroed" - reset/unmark the metaslab being zeroed - if more metaslabs exist, then repeat above tasks. - if no more metaslabs, then we're done. - progress for the initialization is stored on-disk in the vdev’s leaf zap object. The following information is stored: - the last offset that has been initialized - the state of the initialization process (i.e. active, suspended, or canceled) - the start time for the initialization - progress is reported via the zpool status command and shows information for each of the vdevs that are initializing Porting notes: - Added zfs_initialize_value module parameter to set the pattern written by "zpool initialize". - Added zfs_vdev_{initializing,removal}_{min,max}_active module options. Authored by: George Wilson <george.wilson@delphix.com> Reviewed by: John Wren Kennedy <john.kennedy@delphix.com> Reviewed by: Matthew Ahrens <mahrens@delphix.com> Reviewed by: Pavel Zakharov <pavel.zakharov@delphix.com> Reviewed by: Prakash Surya <prakash.surya@delphix.com> Reviewed by: loli10K <ezomori.nozomu@gmail.com> Reviewed by: Brian Behlendorf <behlendorf1@llnl.gov> Approved by: Richard Lowe <richlowe@richlowe.net> Signed-off-by: Tim Chase <tim@chase2k.com> Ported-by: Tim Chase <tim@chase2k.com> OpenZFS-issue: https://www.illumos.org/issues/9102 OpenZFS-commit: https://github.com/openzfs/openzfs/commit/c3963210eb Closes #8230 |
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Tom Caputi
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5aa95ba0d3 |
Fix resilver writes in vdev_indirect_io_start
This patch addresses an issue found in ztest where resilver write zios that were passed to an indirect vdev would end up being handled as though they were resilver read zios. This caused issues where the zio->io_abd would be both read to and written from at the same time, causing asserts to fail. Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov> Reviewed by: Matt Ahrens <matt@delphix.com> Reviewed-by: Serapheim Dimitropoulos <serapheim@delphix.com> Signed-off-by: Tom Caputi <tcaputi@datto.com> Closes #8193 |
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Tom Caputi
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20eb30d08e |
Fix divide by zero during indirect split damage
This patch simply ensures that vdev_indirect_splits_damage() cannot hit a divide by zero exception if a split has no children with valid data. The normal reconstruction code path in vdev_indirect_reconstruct_io_done() already has this check. Reviewed-by: Matthew Ahrens <mahrens@delphix.com> Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Tom Caputi <tcaputi@datto.com> Closes #8086 |
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Tom Caputi
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4a7eb69a5a |
Fix ztest deadman panic with indirect vdev damage
This patch fixes an issue where ztest's deadman thread would trigger a panic because reconstructing artifically damaged blocks would take too long to reconstruct. This patch simply limits how often ztest inflicts split-block damage and how many segments it can damage when it does. Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov> Reviewed-by: Serapheim Dimitropoulos <serapheim.dimitro@delphix.com> Reviewed-by: Matthew Ahrens <mahrens@delphix.com> Signed-off-by: Tom Caputi <tcaputi@datto.com> Closes #8010 |
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Brian Behlendorf
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27f80e85c2 |
Improved error handling for extreme rewinds
The vdev_checkpoint_sm_object(), vdev_obsolete_sm_object(), and vdev_obsolete_counts_are_precise() functions assume that the only way a zap_lookup() can fail is if the requested entry is missing. While this is the most common cause, it's not the only cause. Attemping to access a damaged ZAP will result in other errors. The most likely scenario for accessing a damaged ZAP is during an extreme rewind pool import. Under these conditions the pool is expected to contain damaged objects and the import code was updated to handle this gracefully. Getting an ECKSUM error from these ZAPs after the pool in import a far less likely, therefore the behavior for call paths was not modified. Reviewed-by: Tim Chase <tim@chase2k.com> Reviewed-by: Matthew Ahrens <mahrens@delphix.com> Reviewed-by: Serapheim Dimitropoulos <serapheim.dimitro@delphix.com> Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Closes #7809 Closes #7921 |
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Brian Behlendorf
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1258bd778e
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Refine split block reconstruction
Due to a flaw in
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Serapheim Dimitropoulos
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4d044c4c1d |
OpenZFS 9238 - ZFS Spacemap Encoding V2
Motivation ========== The current space map encoding has the following disadvantages: [1] Assuming 512 sector size each entry can represent at most 16MB for a segment. This makes the encoding very inefficient for large regions of space. [2] As vdev-wide space maps have started to be used by new features (i.e. device removal, zpool checkpoint) we've started imposing limits in the vdevs that can be used with them based on the maximum addressable offset (currently 64PB for a top-level vdev). New encoding ============ The layout can be found at space_map.h and it remains backwards compatible with the old one. The introduced two-word entry format, besides extending the limits imposed by the single-entry layout, also includes a vdev field and some extra padding after its prefix. The extra padding after the prefix should is reserved for future usage (e.g. new prefixes for future encodings or new fields for flags). The new vdev field not only makes the space maps more self-descriptive, but also opens the doors for pool-wide space maps (expected to be used in the log spacemap project). One final important note is that the number of bits used for vdevs is reduced to 24 bits for blkptrs. That was decided as we don't know of any setups that use more than 16M vdevs for the time being and we wanted to fit the vdev field in the space map. In addition that gives us some extra bits in dva_t. Other references: ================= The new encoding is also discussed towards the end of the Log Space Map presentation from 2017's OpenZFS summit. Link: https://www.youtube.com/watch?v=jj2IxRkl5bQ Authored by: Serapheim Dimitropoulos <serapheim@delphix.com> Reviewed by: Matt Ahrens <mahrens@delphix.com> Reviewed by: George Wilson <gwilson@zfsmail.com> Reviewed by: Brian Behlendorf <behlendorf1@llnl.gov> Approved by: Gordon Ross <gwr@nexenta.com> Ported-by: Tim Chase <tim@chase2k.com> Signed-off-by: Tim Chase <tim@chase2k.com> OpenZFS-commit: https://github.com/openzfs/openzfs/commit/90a56e6d OpenZFS-issue: https://www.illumos.org/issues/9238 Closes #7665 |
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Serapheim Dimitropoulos
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d2734cce68 |
OpenZFS 9166 - zfs storage pool checkpoint
Details about the motivation of this feature and its usage can be found in this blogpost: https://sdimitro.github.io/post/zpool-checkpoint/ A lightning talk of this feature can be found here: https://www.youtube.com/watch?v=fPQA8K40jAM Implementation details can be found in big block comment of spa_checkpoint.c Side-changes that are relevant to this commit but not explained elsewhere: * renames members of "struct metaslab trees to be shorter without losing meaning * space_map_{alloc,truncate}() accept a block size as a parameter. The reason is that in the current state all space maps that we allocate through the DMU use a global tunable (space_map_blksz) which defauls to 4KB. This is ok for metaslab space maps in terms of bandwirdth since they are scattered all over the disk. But for other space maps this default is probably not what we want. Examples are device removal's vdev_obsolete_sm or vdev_chedkpoint_sm from this review. Both of these have a 1:1 relationship with each vdev and could benefit from a bigger block size. Porting notes: * The part of dsl_scan_sync() which handles async destroys has been moved into the new dsl_process_async_destroys() function. * Remove "VERIFY(!(flags & FWRITE))" in "kernel.c" so zhack can write to block device backed pools. * ZTS: * Fix get_txg() in zpool_sync_001_pos due to "checkpoint_txg". * Don't use large dd block sizes on /dev/urandom under Linux in checkpoint_capacity. * Adopt Delphix-OS's setting of 4 (spa_asize_inflation = SPA_DVAS_PER_BP + 1) for the checkpoint_capacity test to speed its attempts to fill the pool * Create the base and nested pools with sync=disabled to speed up the "setup" phase. * Clear labels in test pool between checkpoint tests to avoid duplicate pool issues. * The import_rewind_device_replaced test has been marked as "known to fail" for the reasons listed in its DISCLAIMER. * New module parameters: zfs_spa_discard_memory_limit, zfs_remove_max_bytes_pause (not documented - debugging only) vdev_max_ms_count (formerly metaslabs_per_vdev) vdev_min_ms_count Authored by: Serapheim Dimitropoulos <serapheim.dimitro@delphix.com> Reviewed by: Matthew Ahrens <mahrens@delphix.com> Reviewed by: John Kennedy <john.kennedy@delphix.com> Reviewed by: Dan Kimmel <dan.kimmel@delphix.com> Reviewed by: Brian Behlendorf <behlendorf1@llnl.gov> Approved by: Richard Lowe <richlowe@richlowe.net> Ported-by: Tim Chase <tim@chase2k.com> Signed-off-by: Tim Chase <tim@chase2k.com> OpenZFS-issue: https://illumos.org/issues/9166 OpenZFS-commit: https://github.com/openzfs/openzfs/commit/7159fdb8 Closes #7570 |
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Brian Behlendorf
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93ce2b4ca5 |
Update build system and packaging
Minimal changes required to integrate the SPL sources in to the ZFS repository build infrastructure and packaging. Build system and packaging: * Renamed SPL_* autoconf m4 macros to ZFS_*. * Removed redundant SPL_* autoconf m4 macros. * Updated the RPM spec files to remove SPL package dependency. * The zfs package obsoletes the spl package, and the zfs-kmod package obsoletes the spl-kmod package. * The zfs-kmod-devel* packages were updated to add compatibility symlinks under /usr/src/spl-x.y.z until all dependent packages can be updated. They will be removed in a future release. * Updated copy-builtin script for in-kernel builds. * Updated DKMS package to include the spl.ko. * Updated stale AUTHORS file to include all contributors. * Updated stale COPYRIGHT and included the SPL as an exception. * Renamed README.markdown to README.md * Renamed OPENSOLARIS.LICENSE to LICENSE. * Renamed DISCLAIMER to NOTICE. Required code changes: * Removed redundant HAVE_SPL macro. * Removed _BOOT from nvpairs since it doesn't apply for Linux. * Initial header cleanup (removal of empty headers, refactoring). * Remove SPL repository clone/build from zimport.sh. * Use of DEFINE_RATELIMIT_STATE and DEFINE_SPINLOCK removed due to build issues when forcing C99 compilation. * Replaced legacy ACCESS_ONCE with READ_ONCE. * Include needed headers for `current` and `EXPORT_SYMBOL`. Reviewed-by: Tony Hutter <hutter2@llnl.gov> Reviewed-by: Olaf Faaland <faaland1@llnl.gov> Reviewed-by: Matthew Ahrens <mahrens@delphix.com> Reviewed-by: Pavel Zakharov <pavel.zakharov@delphix.com> Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> TEST_ZIMPORT_SKIP="yes" Closes #7556 |
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Matthew Ahrens
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0dc2f70c5c |
OpenZFS 9486 - reduce memory used by device removal on fragmented pools
Device removal allocates a new location for each allocated segment on the disk that's being removed. Each allocation results in one entry in the mapping table, which maps from old location + length to new location. When a fragmented disk is removed, this can result in a large number of mapping entries, and thus a large amount of memory consumed by the mapping table. In the worst real-world cases, we've seen around 1GB of RAM per 1TB of storage removed. We can improve on this situation by allocating larger segments, which span across both allocated and free regions of the device being removed. By including free regions in the allocation (and thus mapping), we reduce the number of mapping entries. For example, if we have a 4K allocation followed by 1K free and then 4K allocated, we would allocate 4+1+4 = 9KB, and then move the entire region (including allocated and free parts). In this case we used one mapping where previously we would have used two, but often the ratio is much higher (up to 20:1 in real-world use). We then need to mark the regions that were free on the removing device as free in the new locations, and also obsolete in the mapping entry. This method preserves the fragmentation of the removing device, rather than consolidating its allocated space into a small number of chunks where possible. But it results in drastic reduction of memory used by the mapping table - around 20x in the most-fragmented cases. In the most fragmented real-world cases, this reduces memory used by the mapping from ~1GB to ~50MB of RAM per 1TB of storage removed. Less fragmented cases will typically also see around 50-100MB of RAM per 1TB of storage. Porting notes: * Add the following as module parameters: * zfs_condense_indirect_vdevs_enable * zfs_condense_max_obsolete_bytes * Document the following module parameters: * zfs_condense_indirect_vdevs_enable * zfs_condense_max_obsolete_bytes * zfs_condense_min_mapping_bytes Authored by: Matthew Ahrens <mahrens@delphix.com> Reviewed by: Brian Behlendorf <behlendorf1@llnl.gov> Ported-by: Tim Chase <tim@chase2k.com> Signed-off-by: Tim Chase <tim@chase2k.com> OpenZFS-issue: https://illumos.org/issues/9486 OpenZFS-commit: https://github.com/ahrens/illumos/commit/07152e142e44c External-issue: DLPX-57962 Closes #7536 |
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Mark Wright
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089500e792 |
Fix CONFIG_GCC_PLUGIN_RANDSTRUCT build
Fix build errors with gcc 7.3.0 on Gentoo with kernel 4.16.3 built with CONFIG_GCC_PLUGIN_RANDSTRUCT=y such as: module/zfs/vdev_indirect.c:296:2: error: positional initialization of field in ‘struct’ declared with ‘designated_init’ attribute [-Werror=designated-init] vdev_indirect_map_free, ^~~~~~~~~~~~~~~~~~~~~~ Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov> Reviewed-by: Giuseppe Di Natale <dinatale2@llnl.gov> Signed-off-by: Mark Wright <gienah@gentoo.org> Closes #7464 |
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Serapheim Dimitropoulos
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4bf8108ede |
OpenZFS 9080 - recursive enter of vdev_indirect_rwlock from vdev_indirect_remap()
Authored by: Serapheim Dimitropoulos <serapheim.dimitro@delphix.com> Reviewed by: Matthew Ahrens <mahrens@delphix.com> Reviewed by: George Wilson <george.wilson@delphix.com> Approved by: Hans Rosenfeld <rosenfeld@grumpf.hope-2000.org> Ported-by: Brian Behlendorf <behlendorf1@llnl.gov> OpenZFS-issue: https://illumos.org/issues/9080 OpenZFS-commit: https://github.com/openzfs/openzfs/commit/bdfded42e6 Closes #6900 |
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Serapheim Dimitropoulos
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9d5b524597 |
OpenZFS 9079 - race condition in starting and ending condensing thread for indirect vdevs
The timeline of the race condition is the following: [1] Thread A is about to finish condesing the first vdev in spa_condense_indirect_thread(), so it calls the spa_condense_indirect_complete_sync() sync task which sets the spa_condensing_indirect field to NULL. Waiting for the sync task to finish, thread A sleeps until the txg is done. When this happens, thread A will acquire spa_async_lock and set spa_condense_thread to NULL. [2] While thread A waits for the txg to finish, thread B which is running spa_sync() checks whether it should condense the second vdev in vdev_indirect_should_condense() by checking the spa_condensing_indirect field which was set to NULL by spa_condense_indirect_thread() from thread A. So it goes on and tries to spawn a new condensing thread in spa_condense_indirect_start_sync() and the aforementioned assertions fails because thread A has not set spa_condense_thread to NULL (which is basically the last thing it does before returning). The main issue here is that we rely on both spa_condensing_indirect and spa_condense_thread to signify whether a condensing thread is running. Ideally we would only use one throughout the codebase. In addition, for managing spa_condense_thread we currently use spa_async_lock which basically tights condensing to scrubing when it comes to pausing and resuming those actions during spa export. This commit introduces the ZTHR infrastructure, which is basically threads created during spa_load()/spa_create() and exist until we export or destroy the pool. ZTHRs sleep the majority of the time, until they are notified to wake up and do some predefined type of work. In the context of the current bug, a zthr to does the condensing of indirect mappings replacing the older code that used bare kthreads. When a pool is created, the condensing zthr is spawned but sleeps right away, until it is awaken by a signal from spa_sync(). If an existing pool is loaded, the condensing zthr looks if there is anything to condense before going to sleep, in case we were condensing mappings in the pool before it got exported. The benefits of this solution are the following: - The current bug is fixed - spa_condensing_indirect is the sole indicator of whether we are currently condensing or not - condensing is more decoupled from the spa_async_thread related functionality. As a final note, this commit also sets up the path on upstreaming other features that use the ZTHR code like zpool checkpoint and fast clone deletion. Authored by: Serapheim Dimitropoulos <serapheim@delphix.com> Reviewed by: Matt Ahrens <mahrens@delphix.com> Reviewed by: Pavel Zakharov <pavel.zakharov@delphix.com> Approved by: Hans Rosenfeld <rosenfeld@grumpf.hope-2000.org> Ported-by: Tim Chase <tim@chase2k.com> OpenZFS-issue: https://illumos.org/issues/9079 OpenZFS-commit: https://github.com/openzfs/openzfs/commit/3dc606ee Closes #6900 |
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Brian Behlendorf
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4589f3ae4c |
Optimize possible split block search space
Remove duplicate segment copies to minimize the possible search space for reconstruction. Once reduced an accurate assessment can be made regarding the difficulty in reconstructing the block. Also, ztest will now run zdb with zfs_reconstruct_indirect_combinations_max set to 1000000 in an attempt to avoid checksum errors. Reviewed-by: Matthew Ahrens <mahrens@delphix.com> Reviewed-by: Tim Chase <tim@chase2k.com> Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Closes #6900 |
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Matthew Ahrens
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9e052db462 |
OpenZFS 9290 - device removal reduces redundancy of mirrors
Mirrors are supposed to provide redundancy in the face of whole-disk failure and silent damage (e.g. some data on disk is not right, but ZFS hasn't detected the whole device as being broken). However, the current device removal implementation bypasses some of the mirror's redundancy. Note that in no case is incorrect data returned, but we might get a checksum error when we should have been able to find the right data. There are two underlying problems: 1. When we remove a mirror device, we only read one side of the mirror. Since we can't verify the checksum, this side may be silently bad, but the good data is on the other side of the mirror (which we didn't read). This can cause the removal to "bake in" the busted data – all copies of the data in the new location are the same, busted version, while we left the good version behind. The fix for this is to read and copy both sides of the mirror. If the old and new vdevs are mirrors, we will read both sides of the old mirror, and write each copy to the corresponding side of the new mirror. (If the old and new vdevs have a different number of children, we will do this as best as possible.) Even though we aren't verifying checksums, this ensures that as long as there's a good copy of the data, we'll have a good copy after the removal, even if there's silent damage to one side of the mirror. If we're removing a mirror that has some silent damage, we'll have exactly the same damage in the new location (assuming that the new location is also a mirror). 2. When we read from an indirect vdev that points to a mirror vdev, we only consider one copy of the data. This can lead to reduced effective redundancy, because we might read a bad copy of the data from one side of the mirror, and not retry the other, good side of the mirror. Note that the problem is not with the removal process, but rather after the removal has completed (having copied correct data to both sides of the mirror), if one side of the new mirror is silently damaged, we encounter the problem when reading the relocated data via the indirect vdev. Also note that the problem doesn't occur when ZFS knows that one side of the mirror is bad, e.g. when a disk entirely fails or is offlined. The impact is that reads (from indirect vdevs that point to mirrors) may return a checksum error even though the good data exists on one side of the mirror, and scrub doesn't repair all data on the mirror (if some of it is pointed to via an indirect vdev). The fix for this is complicated by "split blocks" - one logical block may be split into two (or more) pieces with each piece moved to a different new location. In this case we need to read all versions of each split (one from each side of the mirror), and figure out which combination of versions results in the correct checksum, and then repair the incorrect versions. This ensures that we supply the same redundancy whether you use device removal or not. For example, if a mirror has small silent errors on all of its children, we can still reconstruct the correct data, as long as those errors are at sufficiently-separated offsets (specifically, separated by the largest block size - default of 128KB, but up to 16MB). Porting notes: * A new indirect vdev check was moved from dsl_scan_needs_resilver_cb() to dsl_scan_needs_resilver(), which was added to ZoL as part of the sequential scrub work. * Passed NULL for zfs_ereport_post_checksum()'s zbookmark_phys_t parameter. The extra parameter is unique to ZoL. * When posting indirect checksum errors the ABD can be passed directly, zfs_ereport_post_checksum() is not yet ABD-aware in OpenZFS. Authored by: Matthew Ahrens <mahrens@delphix.com> Reviewed by: Tim Chase <tim@chase2k.com> Reviewed by: Brian Behlendorf <behlendorf1@llnl.gov> Ported-by: Tim Chase <tim@chase2k.com> OpenZFS-issue: https://illumos.org/issues/9290 OpenZFS-commit: https://github.com/openzfs/openzfs/pull/591 Closes #6900 |
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Matthew Ahrens
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a1d477c24c |
OpenZFS 7614, 9064 - zfs device evacuation/removal
OpenZFS 7614 - zfs device evacuation/removal OpenZFS 9064 - remove_mirror should wait for device removal to complete This project allows top-level vdevs to be removed from the storage pool with "zpool remove", reducing the total amount of storage in the pool. This operation copies all allocated regions of the device to be removed onto other devices, recording the mapping from old to new location. After the removal is complete, read and free operations to the removed (now "indirect") vdev must be remapped and performed at the new location on disk. The indirect mapping table is kept in memory whenever the pool is loaded, so there is minimal performance overhead when doing operations on the indirect vdev. The size of the in-memory mapping table will be reduced when its entries become "obsolete" because they are no longer used by any block pointers in the pool. An entry becomes obsolete when all the blocks that use it are freed. An entry can also become obsolete when all the snapshots that reference it are deleted, and the block pointers that reference it have been "remapped" in all filesystems/zvols (and clones). Whenever an indirect block is written, all the block pointers in it will be "remapped" to their new (concrete) locations if possible. This process can be accelerated by using the "zfs remap" command to proactively rewrite all indirect blocks that reference indirect (removed) vdevs. Note that when a device is removed, we do not verify the checksum of the data that is copied. This makes the process much faster, but if it were used on redundant vdevs (i.e. mirror or raidz vdevs), it would be possible to copy the wrong data, when we have the correct data on e.g. the other side of the mirror. At the moment, only mirrors and simple top-level vdevs can be removed and no removal is allowed if any of the top-level vdevs are raidz. Porting Notes: * Avoid zero-sized kmem_alloc() in vdev_compact_children(). The device evacuation code adds a dependency that vdev_compact_children() be able to properly empty the vdev_child array by setting it to NULL and zeroing vdev_children. Under Linux, kmem_alloc() and related functions return a sentinel pointer rather than NULL for zero-sized allocations. * Remove comment regarding "mpt" driver where zfs_remove_max_segment is initialized to SPA_MAXBLOCKSIZE. Change zfs_condense_indirect_commit_entry_delay_ticks to zfs_condense_indirect_commit_entry_delay_ms for consistency with most other tunables in which delays are specified in ms. * ZTS changes: Use set_tunable rather than mdb Use zpool sync as appropriate Use sync_pool instead of sync Kill jobs during test_removal_with_operation to allow unmount/export Don't add non-disk names such as "mirror" or "raidz" to $DISKS Use $TEST_BASE_DIR instead of /tmp Increase HZ from 100 to 1000 which is more common on Linux removal_multiple_indirection.ksh Reduce iterations in order to not time out on the code coverage builders. removal_resume_export: Functionally, the test case is correct but there exists a race where the kernel thread hasn't been fully started yet and is not visible. Wait for up to 1 second for the removal thread to be started before giving up on it. Also, increase the amount of data copied in order that the removal not finish before the export has a chance to fail. * MMP compatibility, the concept of concrete versus non-concrete devices has slightly changed the semantics of vdev_writeable(). Update mmp_random_leaf_impl() accordingly. * Updated dbuf_remap() to handle the org.zfsonlinux:large_dnode pool feature which is not supported by OpenZFS. * Added support for new vdev removal tracepoints. * Test cases removal_with_zdb and removal_condense_export have been intentionally disabled. When run manually they pass as intended, but when running in the automated test environment they produce unreliable results on the latest Fedora release. They may work better once the upstream pool import refectoring is merged into ZoL at which point they will be re-enabled. Authored by: Matthew Ahrens <mahrens@delphix.com> Reviewed-by: Alex Reece <alex@delphix.com> Reviewed-by: George Wilson <george.wilson@delphix.com> Reviewed-by: John Kennedy <john.kennedy@delphix.com> Reviewed-by: Prakash Surya <prakash.surya@delphix.com> Reviewed by: Richard Laager <rlaager@wiktel.com> Reviewed by: Tim Chase <tim@chase2k.com> Reviewed by: Brian Behlendorf <behlendorf1@llnl.gov> Approved by: Garrett D'Amore <garrett@damore.org> Ported-by: Tim Chase <tim@chase2k.com> Signed-off-by: Tim Chase <tim@chase2k.com> OpenZFS-issue: https://www.illumos.org/issues/7614 OpenZFS-commit: https://github.com/openzfs/openzfs/commit/f539f1eb Closes #6900 |