FreeNAS is getting hung sporadically, suspecting OS disk activity

[mosh]

Hi,
I'm seeing that freenas is getting hung for a few minutes (1-5min) sporadically
checking the graphs, I can see a big disk activity on the OS disk, causing a large IO busy

I attached some pictures that describe this peak activity

How can I debug this in order to understand what is the cause for this spike in disk activity?


My server:
FreeNAS-9.10.2-U4 (27ae72978)
Intel(R) Xeon(R) CPU E5-2620 v4 @ 2.10GHz
256GB RAM

 

[Alecmascot]

What hardware is the boot drive ?

 

[mosh]

What hardware is the boot drive ?

Thank you for replying
Its ssd
Full details below

nas4# egrep 'da[5-6]' /var/run/dmesg.boot
da6 at mps0 bus 0 scbus10 target 6 lun 0
da6: <ATA SSDSC2BB120G7R DL41> Fixed Direct Access SPC-4 SCSI device
da6: Serial Number PHDV651400BD150MG
da6: 600.000MB/s transfers
da6: Command Queueing enabled
da6: 114473MB (234441648 512 byte sectors)
da5 at mps0 bus 0 scbus10 target 5 lun 0
da5: <ATA SSDSC2BB120G7R DL41> Fixed Direct Access SPC-4 SCSI device
da5: Serial Number PHDV6514003P150MG
da5: 600.000MB/s transfers
da5: Command Queueing enabled
da5: 114473MB (234441648 512 byte sectors)
nas4#

 

[mosh]

Root Cause: A network glitch, unrelated to FreeNAS.