Freenas restart when Backing Up or move vm between iSCSI lun

[baby27784]

hi every one
I have freenas server that serves as iSCSI san for vms.

pool status is HEALTHY but in Alerts i see :

• CRITICAL: June 23, 2019, 3:32 p.m. - Device: /dev/ciss0 [cciss_disk_11] [SCSI], SMART Failure: FAILURE PREDICTION THRESHOLD EXCEEDED: ascq=0x99
• CRITICAL: June 23, 2019, 3:32 p.m. -Device: /dev/ciss0 [cciss_disk_12] [SCSI], SMART Failure: FAILURE PREDICTION THRESHOLD EXCEEDED: ascq=0x5
• CRITICAL: June 24, 2019, 5:30 p.m. -The volume IT state is ONLINE: One or more devices has experienced an error resulting in data corruption. Applications may be affected.

when we move vm from IT lun to other or backup from IT LUN or restore to IT LUN, freenas restarts.
IT LUN has 4 stripe drive.

is restart due to the device failure in IT pool?
how can i identify root of these failure?
how could move vm to HEALTHY pool?

 

[dlavigne]

What are the hardware specs for the system? Which version of FreeNAS?

 

[baby27784]

What are the hardware specs for the system? Which version of FreeNAS?

HP DL380 G7 16Bay
Ram : 16Gig
CPU: 2*E5620
Nic: 4*1Gig
FreeNas : FreeNAS-11.2-U4

 

[dlavigne]

Were you able to determine the cause for this? Does the issue persist after updating to 11.2-U5?

 

[baby27784]

Were you able to determine the cause for this? Does the issue persist after updating to 11.2-U5?

the root cause was failed drive in strip pool.( no redundancy)
when i removed them problem resolved.
backup from all other mirror pool is ok.