I recently had some server downtime for my office Proxmox server over Christmas and took the opportunity to upgrade to 4.1 from 3.4, and everything seemed to go alright. However, now everyone's back in the office, i'm noticing a severe slowdown across the whole system.
I set up a Zabbix server (in a container on this server) months ago, and that's recorded a marked increase in system-wide IOwait since the upgrade. The system itself was switched off for about a week while we had some electrical work done, but other than that, the upgrade is the only change that's taken place.
Here is a graph from before the upgrade took place:
The spike in iowait corresponds with the nightly backup; that's no problem. The data resolution is decreased slightly because the data is more than 7 days old.
Here's a graph from after the upgrade:
As you can see, the iowait is not huge, but it is causing a severe slowdown on our MySQL VM that's making some of our business software almost unusable.
The server is a Lenovo TS140 with a Xeon E3-1225 v3, 16GB of RAM and two 500GB SATA disks in software RAID 1 and LVM with a 333GB data partition and a 100GB root partition (both ext3 with default mount options). I know software RAID isn't officially advised but we're saving up for a hardware RAID card, and it's not caused any problems for the last 18 months.
There's nothing particularly strange in any of the logs I know about, but i'm not terrible experienced with these things, and any advice would be greatly appreciated.
I set up a Zabbix server (in a container on this server) months ago, and that's recorded a marked increase in system-wide IOwait since the upgrade. The system itself was switched off for about a week while we had some electrical work done, but other than that, the upgrade is the only change that's taken place.
Here is a graph from before the upgrade took place:

The spike in iowait corresponds with the nightly backup; that's no problem. The data resolution is decreased slightly because the data is more than 7 days old.
Here's a graph from after the upgrade:

As you can see, the iowait is not huge, but it is causing a severe slowdown on our MySQL VM that's making some of our business software almost unusable.
The server is a Lenovo TS140 with a Xeon E3-1225 v3, 16GB of RAM and two 500GB SATA disks in software RAID 1 and LVM with a 333GB data partition and a 100GB root partition (both ext3 with default mount options). I know software RAID isn't officially advised but we're saving up for a hardware RAID card, and it's not caused any problems for the last 18 months.

There's nothing particularly strange in any of the logs I know about, but i'm not terrible experienced with these things, and any advice would be greatly appreciated.