Unable to write to ISCSI NAS4Free disk

[ctmoney]

I have three NAS4Free installs setup and running in my office. I have had them going for several years without issue. In the past few months, suddenly two of the NAS devices have crashed repeatedly. I was unable to resolve the issue in the past, so to fix I did a reset to factory defaults in the NAS4Free interface and rebuilt the device. This is the second time this specific device has crashed so it looks to be a bigger issue. I am receiving the following errors in the logs of the NAS device.

Aug 12 20:05:24 nas4free istgt[5007]: istgt_lu_disk.c:6351:istgt_lu_disk_execute: ***ERROR*** lu_disk_lbwrite() failed
Aug 12 20:05:24 nas4free istgt[5007]: istgt_lu_disk.c:4168:istgt_lu_disk_lbwrite: ***ERROR*** lu_disk_write() failed
Aug 12 20:05:24 nas4free istgt[5007]: istgt_lu_disk.c:6351:istgt_lu_disk_execute: ***ERROR*** lu_disk_lbwrite() failed
Aug 12 20:05:24 nas4free istgt[5007]: istgt_lu_disk.c:4168:istgt_lu_disk_lbwrite: ***ERROR*** lu_disk_write() failed
Aug 12 20:05:24 nas4free istgt[5007]: istgt_lu_disk.c:6351:istgt_lu_disk_execute: ***ERROR*** lu_disk_lbwrite() failed
Aug 12 20:05:24 nas4free istgt[5007]: istgt_lu_disk.c:4168:istgt_lu_disk_lbwrite: ***ERROR*** lu_disk_write() failed
Aug 12 20:05:24 nas4free istgt[5007]: istgt_lu_disk.c:6351:istgt_lu_disk_execute: ***ERROR*** lu_disk_lbwrite() failed
Aug 12 20:05:24 nas4free istgt[5007]: istgt_lu_disk.c:4168:istgt_lu_disk_lbwrite: ***ERROR*** lu_disk_write() failed

There are hundreds of these errors repeated in the logs. The ISSCI disk is still showing available to the Windows server that is connecting to the NAS, but once I try to write to the disk I receive these errors and the write fails.

The NAS4Free install is setup as follows:
ISCSI host
ZFS Pool raidz3

One interesting item I have found, disk space usage on the system information screen is showing 96% capacity, 10.5T allocated of the total 10.9T. Not sure why there is so much disk space being used. I provisioned the ISCSI target to only use 8T.

Your help is much appreciated!

[Lord Crc]

One interesting item I have found, disk space usage on the system information screen is showing 96% capacity, 10.5T allocated of the total 10.9T. Not sure why there is so much disk space being used. I provisioned the ISCSI target to only use 8T.

The total on the system information screen is total disk space, but not total usable space. Redundancy (raidz) is also allocated from the "free space" for example, and the redundancy is included in the total space.

However the iSCSI target is "usable space", so the diskspace required is 8TB + redundancy.

So, I guess you're running out of disk space and that's why the iSCSI is failing.

See https://www.delphix.com/blog/delphix-en ... love-raidz for details on raidz overhead.