Slower iSCSI performance on Windows Server 2022

[TinchoB]

Hello,
We had an old Backup/Repository Server (DELL R730) to backup a VMWARE Cluster. It had Windows 2019 as OS and used to be connected via 10G Ethernet to an ISCSI Dell ME4012 backup Storage (ethernet direct attach without network switches). Veeam v12.3.2 and SQL 2017 as config database. We didnt use ReFS. Backup performance was very good.

As the old Sever reached end of support, some weeks ago we moved to a new Dell Server (R760) with Windows 2022 as OS and SQL 2017 as configuration database, but retained the old ISCSI Backup Storage (reconnecting it to the new Server). Also not using ReFS.

At first backup Jobs seems to run fine but comparing executions times and performance with the old Server, we realized a significant reduction in the writing performance to the iSCSI storage. Veeam JOBs report a much higher load on the Target repository, and in Windows performance monitor disk queue for this ISCSI disk is also higher.

It´s very extrange because we didnt change anything in the Storage itself. JOBs, Repository and Veeam config are all the same. We set Jubo frames as in the old Server and all seems to be ok, but for some unknown reason repository performance is slower on Windows 2022 than in Windows 2019.

Has someone experienced a slower iSCSI performance on Windows 2022 ?

Thanks !!

[PetrM]

Hi Martin,

Why not start using ReFS? There are many advantages, including reduced disk space requirements and faster synthetic operations with minimal storage device load.

Thanks!

[TinchoB]

Hello Petr,
because by internal policy we execute an Active Full Backup every Saturday (no synthetics), so NTFS was good for us.

Regarding the performance issue, until now (with Windows 2019) we had very good processing numbers, we almost got 100% of the 10Gb/s link to the iSCSI Target. But dont know why with Windows 2022 we only got 50% (or less) with the same config.

[PetrM]

Hi Martin,

Well, I don't think I can suggest anything except checking that all the drivers are up to date, OS updates are installed, and there is no antivirus software or any scheduled background tasks that could impact system performance. Additionally, if you have a network switch over which the iSCSI traffic circulates, it's worth checking the dropped packets statistics.

Thanks!

[RWeiss]

When we upgraded our infrastructure around 2 years ago (Supermicro & Dell 25G Switches), we noticed the same thing. We were unable to solve it - had slow performance even with direct connection (i.e. without the Switch in between) and we were unable to solve it - we used Mellanox/Nvidia NICs and Intel NICs without success. We ended up using Server 2019 where we had no issues at all...