Friday, June 09, 2006

fsck, strange files, etc.

In some places I use SATA drives for data storage. From time to time there is a problem with filesystems and I have to fsck, sometimes files are a little bit garbled, etc.
Last time I tried ZFS on SATA disks and to my surprise - just after 3 days I got few hundreds checksum error - well, that explains a lot. Then it stabilized and now from time to time I see occasional errors.

Sometimes we had to live with some problems for so long without any alternative that we have forgotten about a problem and got accustomed to fsck, some bad files, etc.


I would say that ZFS changes that picture radically.
Thanks to ZFS there's no need to fsck, proper data are returned to applications, no mangled fs entries, etc.
It already save our data :)

ps. I haven't yet seen checksum errors reported by ZFS on SCSI, FC or SAS disks...

1 comment:

Anonymous said...

some errors i have with zfs

pool: Volumes
state: ONLINE
status: One or more devices has experienced an error resulting in data
corruption. Applications may be affected.
action: Restore the file in question if possible. Otherwise restore the
entire pool from backup.
see: http://www.sun.com/msg/ZFS-8000-8A
scrub: scrub completed with 422 errors on Fri Jul 7 21:09:41 2006
config:

NAME STATE READ WRITE CKSUM
Volumes ONLINE 0 0 894
c1t2d0s7 ONLINE 0 0 120
c1t2d1s7 ONLINE 0 0 106
c1t2d2s7 ONLINE 0 0 124
c1t2d3s7 ONLINE 0 0 98
c1t2d4s7 ONLINE 0 0 104
c1t2d5s7 ONLINE 0 0 104
c1t2d6s7 ONLINE 0 0 118
c1t2d7s7 ONLINE 0 0 120

errors: The following persistent errors have been detected:

DATASET OBJECT RANGE
Volumes/Archiv3 219398 8650752-8781824
Volumes/Archiv2 177834 6946816-7077888
Volumes/Archiv2 178323 393216-524288
Volumes/Archiv2 178418 35389440-35520512
Volumes/Archiv2 178590 12976128-13107200
Volumes/Archiv2 178745 112590848-112721920
Volumes/Archiv2 178915 10092544-10223616
Volumes/Archiv2 178926 81657856-81788928
Volumes/Archiv2 178928 86507520-86638592
Volumes/Archiv2 180047 11534336-11665408
Volumes/Archiv2 180371 1310720-1441792
Volumes/Archiv2 181018 524288-655360
Volumes/Archiv2 181288 22675456-22806528
Volumes/Archiv2 181305 49545216-49676288
Volumes/Archiv2 181312 278659072-278790144
Volumes/Archiv2 181316 76808192-76939264
Volumes/Archiv2 181438 6160384-6291456
Volumes/Archiv2 181454 126615552-126746624
Volumes/Archiv2 181498 23199744-23330816
Volumes/Archiv2 181537 27131904-27262976
Volumes/Archiv2 182066 31195136-31326208
Volumes/Archiv2 182219 46530560-46661632
Volumes/Archiv2 182285 7077888-7208960
Volumes/Archiv2 182449 1441792-1572864
Volumes/Archiv2 182531 1048576-1179648
Volumes/Archiv2 183245 195821568-195952640


The problem i see, if there is not a mirror for ZFS, ZFS is not able to correct defekt data blocks.