diff options
Diffstat (limited to 'cmd/zfs/zfs_main.c')
| -rw-r--r-- | cmd/zfs/zfs_main.c | 130 |
1 files changed, 118 insertions, 12 deletions
diff --git a/cmd/zfs/zfs_main.c b/cmd/zfs/zfs_main.c index f609a4e70..340a7db96 100644 --- a/cmd/zfs/zfs_main.c +++ b/cmd/zfs/zfs_main.c @@ -893,6 +893,107 @@ usage: } /* + * Return a default volblocksize for the pool which always uses more than + * half of the data sectors. This primarily applies to dRAID which always + * writes full stripe widths. + */ +static uint64_t +default_volblocksize(zpool_handle_t *zhp, nvlist_t *props) +{ + uint64_t volblocksize, asize = SPA_MINBLOCKSIZE; + nvlist_t *tree, **vdevs; + uint_t nvdevs; + + nvlist_t *config = zpool_get_config(zhp, NULL); + + if (nvlist_lookup_nvlist(config, ZPOOL_CONFIG_VDEV_TREE, &tree) != 0 || + nvlist_lookup_nvlist_array(tree, ZPOOL_CONFIG_CHILDREN, + &vdevs, &nvdevs) != 0) { + return (ZVOL_DEFAULT_BLOCKSIZE); + } + + for (int i = 0; i < nvdevs; i++) { + nvlist_t *nv = vdevs[i]; + uint64_t ashift, ndata, nparity; + + if (nvlist_lookup_uint64(nv, ZPOOL_CONFIG_ASHIFT, &ashift) != 0) + continue; + + if (nvlist_lookup_uint64(nv, ZPOOL_CONFIG_DRAID_NDATA, + &ndata) == 0) { + /* dRAID minimum allocation width */ + asize = MAX(asize, ndata * (1ULL << ashift)); + } else if (nvlist_lookup_uint64(nv, ZPOOL_CONFIG_NPARITY, + &nparity) == 0) { + /* raidz minimum allocation width */ + if (nparity == 1) + asize = MAX(asize, 2 * (1ULL << ashift)); + else + asize = MAX(asize, 4 * (1ULL << ashift)); + } else { + /* mirror or (non-redundant) leaf vdev */ + asize = MAX(asize, 1ULL << ashift); + } + } + + /* + * Calculate the target volblocksize such that more than half + * of the asize is used. The following table is for 4k sectors. + * + * n asize blksz used | n asize blksz used + * -------------------------+--------------------------------- + * 1 4,096 8,192 100% | 9 36,864 32,768 88% + * 2 8,192 8,192 100% | 10 40,960 32,768 80% + * 3 12,288 8,192 66% | 11 45,056 32,768 72% + * 4 16,384 16,384 100% | 12 49,152 32,768 66% + * 5 20,480 16,384 80% | 13 53,248 32,768 61% + * 6 24,576 16,384 66% | 14 57,344 32,768 57% + * 7 28,672 16,384 57% | 15 61,440 32,768 53% + * 8 32,768 32,768 100% | 16 65,536 65,636 100% + * + * This is primarily a concern for dRAID which always allocates + * a full stripe width. For dRAID the default stripe width is + * n=8 in which case the volblocksize is set to 32k. Ignoring + * compression there are no unused sectors. This same reasoning + * applies to raidz[2,3] so target 4 sectors to minimize waste. + */ + uint64_t tgt_volblocksize = ZVOL_DEFAULT_BLOCKSIZE; + while (tgt_volblocksize * 2 <= asize) + tgt_volblocksize *= 2; + + const char *prop = zfs_prop_to_name(ZFS_PROP_VOLBLOCKSIZE); + if (nvlist_lookup_uint64(props, prop, &volblocksize) == 0) { + + /* Issue a warning when a non-optimal size is requested. */ + if (volblocksize < ZVOL_DEFAULT_BLOCKSIZE) { + (void) fprintf(stderr, gettext("Warning: " + "volblocksize (%llu) is less than the default " + "minimum block size (%llu).\nTo reduce wasted " + "space a volblocksize of %llu is recommended.\n"), + (u_longlong_t)volblocksize, + (u_longlong_t)ZVOL_DEFAULT_BLOCKSIZE, + (u_longlong_t)tgt_volblocksize); + } else if (volblocksize < tgt_volblocksize) { + (void) fprintf(stderr, gettext("Warning: " + "volblocksize (%llu) is much less than the " + "minimum allocation\nunit (%llu), which wastes " + "at least %llu%% of space. To reduce wasted " + "space,\nuse a larger volblocksize (%llu is " + "recommended), fewer dRAID data disks\n" + "per group, or smaller sector size (ashift).\n"), + (u_longlong_t)volblocksize, (u_longlong_t)asize, + (u_longlong_t)((100 * (asize - volblocksize)) / + asize), (u_longlong_t)tgt_volblocksize); + } + } else { + volblocksize = tgt_volblocksize; + fnvlist_add_uint64(props, prop, volblocksize); + } + + return (volblocksize); +} + +/* * zfs create [-Pnpv] [-o prop=value] ... fs * zfs create [-Pnpsv] [-b blocksize] [-o prop=value] ... -V vol size * @@ -932,6 +1033,7 @@ zfs_do_create(int argc, char **argv) int ret = 1; nvlist_t *props; uint64_t intval; + char *strval; if (nvlist_alloc(&props, NV_UNIQUE_NAME, 0) != 0) nomem(); @@ -1018,7 +1120,7 @@ zfs_do_create(int argc, char **argv) goto badusage; } - if (dryrun || (type == ZFS_TYPE_VOLUME && !noreserve)) { + if (dryrun || type == ZFS_TYPE_VOLUME) { char msg[ZFS_MAX_DATASET_NAME_LEN * 2]; char *p; @@ -1040,18 +1142,24 @@ zfs_do_create(int argc, char **argv) } } - /* - * if volsize is not a multiple of volblocksize, round it up to the - * nearest multiple of the volblocksize - */ if (type == ZFS_TYPE_VOLUME) { - uint64_t volblocksize; + const char *prop = zfs_prop_to_name(ZFS_PROP_VOLBLOCKSIZE); + uint64_t volblocksize = default_volblocksize(zpool_handle, + real_props); - if (nvlist_lookup_uint64(props, - zfs_prop_to_name(ZFS_PROP_VOLBLOCKSIZE), - &volblocksize) != 0) - volblocksize = ZVOL_DEFAULT_BLOCKSIZE; + if (volblocksize != ZVOL_DEFAULT_BLOCKSIZE && + nvlist_lookup_string(props, prop, &strval) != 0) { + if (asprintf(&strval, "%llu", + (u_longlong_t)volblocksize) == -1) + nomem(); + nvlist_add_string(props, prop, strval); + free(strval); + } + /* + * If volsize is not a multiple of volblocksize, round it + * up to the nearest multiple of the volblocksize. + */ if (volsize % volblocksize) { volsize = P2ROUNDUP_TYPED(volsize, volblocksize, uint64_t); @@ -1064,11 +1172,9 @@ zfs_do_create(int argc, char **argv) } } - if (type == ZFS_TYPE_VOLUME && !noreserve) { uint64_t spa_version; zfs_prop_t resv_prop; - char *strval; spa_version = zpool_get_prop_int(zpool_handle, ZPOOL_PROP_VERSION, NULL); |