Performance issue on Synology NAS repository

[govi]

Hi Team

Recently we started to face performance issue while doing backup using Veeam agent for Windows.

Windows Server 2016 VM which is acting as Veeam backup and replication server.
All Veeam Agent for Windows are connected to Backup repository.
Backup repository is Synology NAS which is presented as iSCSI drive to Veeam B& R server.

Past few years this setup was working perfectly and was happy with this setup. Not much performance issue but past few months Windows agent backup jobs is taking too much time to complete.
Jobs which is use to finish in minutes now takes hours to complete.

recently, i have performed below activitity and not sure if any of below activity impacted the performance issue.
1_Upgraded ESXi host from 6.7 to 6.7 latest update and also Vcenter Server upgrade to 6.7 latest upgrade
2_upgraded DELL R730 firmware and drivers to latest version.

NAS side
Had hard disk failure and replaced with brand new WD RED hard disk. Total 4 Hard disk and all are of same brand(WD RED). Configured in RAID 5.
Only Difference i have seen with new hard disk is that new hard disk has different firmware version then older hard disk. Did not find tool which can help to upgrade the firmware. Contacted support and waiting for reply. Not sure if that's possible.I think should not be!
Upgraded DSM to 7.0 version.

Checked iSCSI settings are seems to be fine.

Any pointer or direction i should start investigating? Since i have done so many activities , its hard for me to figure out, what is the root cause. ESXi upgrade is routing task

Many Thanks in Advance.

Thanks
Govi

[karsten123]

what bottleneck is the job showing?

[govi]

Hi karsten123

Thanks for the reply. Bottleneck is showing as target i.e Synology iSCSI Drive.

Thanks,

Govi

[karsten123]

can you see any performance metric hit the ceiling in the synology performance monitor while running the backup?

[govi]

Hi,

Received reply from Synology Support and issue is due to replacement hard disk. Replacement hard disk is not represent in compatibility list of Synology NAS.

Probably its mistake from supplie and i did not bother to check as well.

Below is the exact reason which is mentioned by Synology support. Sharing in the community so that it might help somebody in future.

"Replaced hard disk is SMR and older hard disk are PMR Drives
The mechanism of SMR is different from common PMR drives, you could refer to below FAQ:
https://kb.synology.com/en-global/DSM/t ... isk_drives
For SMR drives, there is continuous I/O based on its mechanism so that the performance would be dragged obviously.
This may be the reason you feel the performance issue occurs all the time.
If you keep using the SMR disk, the performance to retrieve the files or the operate the system may be dragged by the disk1(SMR disk)
In addition, the disk model(XXXXXX) is not listed on Synology Compatibility list.
We strongly suggest you replace the SMR drive1 with a compatible drive, then please monitor if the LUN performance improves"

Thanks

Govi

[karsten123]

SMR
Always check the compatibility lists

[Nils]

Yes, beware of SMR disks for any RAID or any concurrent access scenario.