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Illumos 5027 - zfs large block support

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5027 zfs large block support
Reviewed by: Alek Pinchuk <pinchuk.alek@gmail.com>
Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Josef 'Jeff' Sipek <josef.sipek@nexenta.com>
Reviewed by: Richard Elling <richard.elling@richardelling.com>
Reviewed by: Saso Kiselkov <skiselkov.ml@gmail.com>
Reviewed by: Brian Behlendorf <behlendorf1@llnl.gov>
Approved by: Dan McDonald <danmcd@omniti.com>

References:
  https://www.illumos.org/issues/5027
  https://github.com/illumos/illumos-gate/commit/b515258

Porting Notes:

* Included in this patch is a tiny ISP2() cleanup in zio_init() from
Illumos 5255.

* Unlike the upstream Illumos commit this patch does not impose an
arbitrary 128K block size limit on volumes.  Volumes, like filesystems,
are limited by the zfs_max_recordsize=1M module option.

* By default the maximum record size is limited to 1M by the module
option zfs_max_recordsize.  This value may be safely increased up to
16M which is the largest block size supported by the on-disk format.
At the moment, 1M blocks clearly offer a significant performance
improvement but the benefits of going beyond this for the majority
of workloads are less clear.

* The illumos version of this patch increased DMU_MAX_ACCESS to 32M.
This was determined not to be large enough when using 16M blocks
because the zfs_make_xattrdir() function will fail (EFBIG) when
assigning a TX.  This was immediately observed under Linux because
all newly created files must have a security xattr created and
that was failing.  Therefore, we've set DMU_MAX_ACCESS to 64M.

* On 32-bit platforms a hard limit of 1M is set for blocks due
to the limited virtual address space.  We should be able to relax
this one the ABD patches are merged.

Ported-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #354
This commit is contained in:
Matthew Ahrens
2014-11-03 12:15:08 -08:00
committed by Brian Behlendorf
parent 3df293404a
commit f1512ee61e
55 changed files with 613 additions and 155 deletions
Download Patch File Download Diff File Expand all files Collapse all files
include/sys/spa.h
+16 -6
View File
@@ -98,17 +98,26 @@ _NOTE(CONSTCOND) } while (0)
_NOTE(CONSTCOND) } while (0)
/*
* We currently support nine block sizes, from 512 bytes to 128K.
* We could go higher, but the benefits are near-zero and the cost
* of COWing a giant block to modify one byte would become excessive.
* We currently support block sizes from 512 bytes to 16MB.
* The benefits of larger blocks, and thus larger IO, need to be weighed
* against the cost of COWing a giant block to modify one byte, and the
* large latency of reading or writing a large block.
*
* Note that although blocks up to 16MB are supported, the recordsize
* property can not be set larger than zfs_max_recordsize (default 1MB).
* See the comment near zfs_max_recordsize in dsl_dataset.c for details.
*
* Note that although the LSIZE field of the blkptr_t can store sizes up
* to 32MB, the dnode's dn_datablkszsec can only store sizes up to
* 32MB - 512 bytes. Therefore, we limit SPA_MAXBLOCKSIZE to 16MB.
*/
#define SPA_MINBLOCKSHIFT 9
#define SPA_MAXBLOCKSHIFT 17
#define SPA_OLD_MAXBLOCKSHIFT 17
#define SPA_MAXBLOCKSHIFT 24
#define SPA_MINBLOCKSIZE (1ULL << SPA_MINBLOCKSHIFT)
#define SPA_OLD_MAXBLOCKSIZE (1ULL << SPA_OLD_MAXBLOCKSHIFT)
#define SPA_MAXBLOCKSIZE (1ULL << SPA_MAXBLOCKSHIFT)
#define SPA_BLOCKSIZES (SPA_MAXBLOCKSHIFT - SPA_MINBLOCKSHIFT + 1)
/*
* Size of block to hold the configuration data (a packed nvlist)
*/
@@ -830,6 +839,7 @@ extern boolean_t spa_has_slogs(spa_t *spa);
extern boolean_t spa_is_root(spa_t *spa);
extern boolean_t spa_writeable(spa_t *spa);
extern boolean_t spa_has_pending_synctask(spa_t *spa);
extern int spa_maxblocksize(spa_t *spa);
extern void zfs_blkptr_verify(spa_t *spa, const blkptr_t *bp);
extern int spa_mode(spa_t *spa);