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OpenZFS 7614, 9064 - zfs device evacuation/removal

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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
This commit is contained in:
Matthew Ahrens
2016-09-22 09:30:13 -07:00
committed by Brian Behlendorf
parent 4b0f5b2d7b
commit a1d477c24c
127 changed files with 9864 additions and 914 deletions
Download Patch File Download Diff File Expand all files Collapse all files
include/sys/dmu.h
+9 -2
View File
@@ -326,6 +326,7 @@ int dmu_objset_find(char *name, int func(const char *, void *), void *arg,
void dmu_objset_byteswap(void *buf, size_t size);
int dsl_dataset_rename_snapshot(const char *fsname,
const char *oldsnapname, const char *newsnapname, boolean_t recursive);
int dmu_objset_remap_indirects(const char *fsname);
typedef struct dmu_buf {
uint64_t db_object; /* object that this buffer is part of */
@@ -362,6 +363,9 @@ typedef struct dmu_buf {
#define DMU_POOL_EMPTY_BPOBJ "empty_bpobj"
#define DMU_POOL_CHECKSUM_SALT "org.illumos:checksum_salt"
#define DMU_POOL_VDEV_ZAP_MAP "com.delphix:vdev_zap_map"
#define DMU_POOL_REMOVING "com.delphix:removing"
#define DMU_POOL_OBSOLETE_BPOBJ "com.delphix:obsolete_bpobj"
#define DMU_POOL_CONDENSING_INDIRECT "com.delphix:condensing_indirect"
/*
* Allocate an object from this objset. The range of object numbers
@@ -470,6 +474,8 @@ void dmu_object_set_compress(objset_t *os, uint64_t object, uint8_t compress,
int dmu_object_dirty_raw(objset_t *os, uint64_t object, dmu_tx_t *tx);
int dmu_object_remap_indirects(objset_t *os, uint64_t object, uint64_t txg);
void dmu_write_embedded(objset_t *os, uint64_t object, uint64_t offset,
void *data, uint8_t etype, uint8_t comp, int uncompressed_size,
int compressed_size, int byteorder, dmu_tx_t *tx);
@@ -488,8 +494,8 @@ void dmu_write_policy(objset_t *os, dnode_t *dn, int level, int wp,
* The bonus data is accessed more or less like a regular buffer.
* You must dmu_bonus_hold() to get the buffer, which will give you a
* dmu_buf_t with db_offset==-1ULL, and db_size = the size of the bonus
* data. As with any normal buffer, you must call dmu_buf_read() to
* read db_data, dmu_buf_will_dirty() before modifying it, and the
* data. As with any normal buffer, you must call dmu_buf_will_dirty()
* before modifying it, and the
* object must be held in an assigned transaction before calling
* dmu_buf_will_dirty. You may use dmu_buf_set_user() on the bonus
* buffer as well. You must release what you hold with dmu_buf_rele().
@@ -740,6 +746,7 @@ void dmu_tx_hold_free(dmu_tx_t *tx, uint64_t object, uint64_t off,
uint64_t len);
void dmu_tx_hold_free_by_dnode(dmu_tx_t *tx, dnode_t *dn, uint64_t off,
uint64_t len);
void dmu_tx_hold_remap_l1indirect(dmu_tx_t *tx, uint64_t object);
void dmu_tx_hold_zap(dmu_tx_t *tx, uint64_t object, int add, const char *name);
void dmu_tx_hold_zap_by_dnode(dmu_tx_t *tx, dnode_t *dn, int add,
const char *name);