USBメモリ3本でZFSと同じUSBメモリを使って、今度はraidzでpoolを作成します。
# zpool create -f usbpool5 raidz c6t0d0 c7t0d0 c8t0d0
# zpool status usbpool5
pool: usbpool5
state: ONLINE
scrub: none requested
config:
NAME STATE READ WRITE CKSUM
usbpool5 ONLINE 0 0 0
raidz1 ONLINE 0 0 0
c6t0d0 ONLINE 0 0 0
c7t0d0 ONLINE 0 0 0
c8t0d0 ONLINE 0 0 0
errors: No known data errors
# df -h /usbpool5
Filesystem size used avail capacity Mounted on
usbpool5 3.6G 25K 3.6G 1% /usbpool5
ここから実験のために1GBのファイルを作成します。
# mkfile 1g /usbpool5/1G
# df -h /usbpool5
Filesystem size used avail capacity Mounted on
usbpool5 3.6G 982M 2.6G 27% /usbpool5
その後、３本うち１本をいきなり抜きます。
c7t0d0が見えなくなります。
# rmformat
Looking for devices...
1. Logical Node: /dev/rdsk/c6t0d0p0
Physical Node: /pci@0,0/pci8086,464c@1d,7/storage@1/disk@0,0
Connected Device: Generic USB SD Reader 1.00
Device Type: Removable
Bus: USB
Size: 1.9 GB
Label: <Unknown>
Access permissions: <Unknown>
2. Logical Node: /dev/rdsk/c8t0d0p0
Physical Node: /pci@0,0/pci8086,464c@1d,7/storage@2/disk@0,0
Connected Device: Kingmax USB2.0 FlashDisk 0.00
Device Type: Removable
Bus: USB
Size: 1.9 GB
Label: <Unknown>
Access permissions: <Unknown>
readアクセスしたらエラーがでました。ただしあくまでONLINE。
# dd if=/usbpool5/1G of=/dev/null bs=1024k count=100
100+0 records in
100+0 records out
# zpool status usbpool5
pool: usbpool5
state: ONLINE
status: One or more devices has experienced an unrecoverable error. An
attempt was made to correct the error. Applications are unaffected.
action: Determine if the device needs to be replaced, and clear the errors
using 'zpool clear' or replace the device with 'zpool replace'.
see: http://www.sun.com/msg/ZFS-8000-9P
scrub: none requested
config:
NAME STATE READ WRITE CKSUM
usbpool5 ONLINE 0 0 0
raidz1 ONLINE 0 0 0
c6t0d0 ONLINE 0 0 0
c7t0d0 ONLINE 3 0 0
c8t0d0 ONLINE 0 0 0
errors: No known data errors
100MBほど書き込むとエラーが大量に出てREMOVEDとなりました。
# mkfile 100m /usbpool5/100m
# zpool status usbpool5
pool: usbpool5
state: DEGRADED
status: One or more devices has experienced an unrecoverable error. An
attempt was made to correct the error. Applications are unaffected.
action: Determine if the device needs to be replaced, and clear the errors
using 'zpool clear' or replace the device with 'zpool replace'.
see: http://www.sun.com/msg/ZFS-8000-9P
scrub: none requested
config:
NAME STATE READ WRITE CKSUM
usbpool5 DEGRADED 0 0 0
raidz1 DEGRADED 0 0 0
c6t0d0 ONLINE 0 0 0
c7t0d0 REMOVED 0 598 0
c8t0d0 ONLINE 0 0 0
errors: No known data errors
ここでUSBを挿しなおすと、再びc7t0d0と認識されたため、
挿した瞬間からscrub(RAIDの再構築)が自動的に行われました。
# zpool status usbpool5
pool: usbpool5
state: ONLINE
status: One or more devices has experienced an unrecoverable error. An
attempt was made to correct the error. Applications are unaffected.
action: Determine if the device needs to be replaced, and clear the errors
using 'zpool clear' or replace the device with 'zpool replace'.
see: http://www.sun.com/msg/ZFS-8000-9P
scrub: resilver completed after 0h0m with 0 errors on Sun May 24 23:29:35 2009
config:
NAME STATE READ WRITE CKSUM
usbpool5 ONLINE 0 0 0
raidz1 ONLINE 0 0 0
c6t0d0 ONLINE 0 0 0
c7t0d0 ONLINE 0 1.54K 0 50.1M resilvered
c8t0d0 ONLINE 0 0 0
errors: No known data errors
ここで注目は「50.1M resilvered」というところです。
2GBのメディアですが、全体を再構築するわけでもなければ、
以前書き込まれていた1GBのファイルを再書き込みするわけでもなく、
このメディア抜かれていた間に書き込まれた100MBのファイルの部分だけです。
もし全く新しいメディアでreplaceした場合でも、1GB+100MBの使用中部分だけの
再構築で済むのがZFSのいいところです。
最後に zpool clear をすれば元通りです。
# zpool clear usbpool5
# zpool status usbpool5
pool: usbpool5
state: ONLINE
scrub: resilver completed after 0h0m with 0 errors on Sun May 24 23:29:35 2009
config:
NAME STATE READ WRITE CKSUM
usbpool5 ONLINE 0 0 0
raidz1 ONLINE 0 0 0
c6t0d0 ONLINE 0 0 0
c7t0d0 ONLINE 0 0 0 50.1M resilvered
c8t0d0 ONLINE 0 0 0
errors: No known data errors