zfsonlinux/zfs — Issue #591: zpool is resilvering on startup 
Author: pyavdr
Created: 2012-03-01 19:03:08+00:00
State: open

My Ubuntu 10.10 Server with latest zfs/spl (03/01/2012) from github is resilvering my pool on startup from time to time.
pool: stor1
state: ONLINE
scan: resilvered 1K in 0h0m with 0 errors on Thu Mar 1 18:52:46 2012
config:

NAME STATE READ WRITE CKSUM
stor1 ONLINE 0 0 0
raidz1-0 ONLINE 0 0 0
ata-ST31500341ASxxx ONLINE 0 0 0
ata-ST31500341ASxxx	ONLINE 0 0 0
scsi-35000cxxx	ONLINE 0 0 0
scsi-35000cxxx	ONLINE 0 0 0
scsi-35000cxxx	ONLINE 0 0 0
scsi-35000cxxx	ONLINE 0 0 0
scsi-35000cxxx	ONLINE 0 0 0
scsi-35000cxxx	ONLINE 0 0 0
scsi-35000cxxx	ONLINE 0 0 0
scsi-35000cxxx	ONLINE 0 0 0

errors: No known data errors

I checked the disks/cabling, the smartvalues and so on, nothing special.
There are no errors in dmesg on startup, all disk are up and running before ZFS starts.
The amount of data resilvered on startup is varying, from 1k to 13k,
sometimes there are some (1-5) chksum errors on on of the disks.
The checksum error disappear after a few seconds.

Questions:
Is it ok to shutdown with on "sync;sync;poweroff" ?
What condition triggers the resilvering?
Maybe an error in the driver for the Intel RS2WC080 controller ?
Maybe an harddisk error ( the checksum error is only on one disk)?
Any other causes ?

Thanks