diff options
Diffstat (limited to 'include/sys/spa.h')
| -rw-r--r-- | include/sys/spa.h | 22 |
1 files changed, 16 insertions, 6 deletions
diff --git a/include/sys/spa.h b/include/sys/spa.h index 834ad005a..5dc9084da 100644 --- a/include/sys/spa.h +++ b/include/sys/spa.h @@ -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); |