Hello!
I've been using PROXMOX in a dedicated server since Sept. 2012. My hardware includes 16gb of ram, two INTEL 180gb SSD 520 disks in RAID1 (using a 3ware 9650SE-2LP card) and an INTEL 1230v2 quadcore xeon processor.
Everything was lightning fast at first. Fsyncs/second where about 2500 ... Also I had about 70gb of free space on the SSD.
Recently I did create some VM backups, and almost filled up the SSD. Then I proceeded to delete thos backup files, once I downloaded it into local space.
I started noticing some slowing down ... particularly in a windows 2003 server I am running as KVM inside my proxmox: Copying or deleting files inside that virtual machine was painfully slow.
Finally I started issueing pveperf commands to monitor my server, only to find a drastic decrease in FSYNC/second values, which now gives back a value oscillating between 23 - 40 .
Also the PROXMOX status shows a high IOWAIT (I recall IOWAIT being virtually ZERO before things started going down the hill).
I did my resarch, and I found out that HARDWARE RAID1 cards do not pass through the TRIM commands that LINUX may be sending, so you should entirely depend on the internal garbage collection capabilities of the SSD itself. Which actually usually triggers when the SSD is "iddle" (which won't happen under "proxmox hammering" even with one virtual machine).
Hence, I realized that my SSD RAID1 is having a bad time consolidating free space whenever PROXMOX asks for a write operation. Maybe I am wrong. I would like very much if anyone wants me to provide more information, or perform some tests ...
I am trying to make my dedicated server provider to change the raid1 disks into INTEL S3700 which seems to be much more resilient to write operations, and also got a better garbage collection system, that -if I understood correctly- is constantly running in the background (does not wait for the SSD to be "iddle" to perform it's magic).
Also, it may be a "heads up" for SSD / RAID1 guys ... specially if those arrays have been stuffed with "desktop graded" SSDs, like the INTEL 520 series, which is my case. It may take months, or over a year, but IOWAIT will catch ya!
I've been using PROXMOX in a dedicated server since Sept. 2012. My hardware includes 16gb of ram, two INTEL 180gb SSD 520 disks in RAID1 (using a 3ware 9650SE-2LP card) and an INTEL 1230v2 quadcore xeon processor.
Everything was lightning fast at first. Fsyncs/second where about 2500 ... Also I had about 70gb of free space on the SSD.
Recently I did create some VM backups, and almost filled up the SSD. Then I proceeded to delete thos backup files, once I downloaded it into local space.
I started noticing some slowing down ... particularly in a windows 2003 server I am running as KVM inside my proxmox: Copying or deleting files inside that virtual machine was painfully slow.
Finally I started issueing pveperf commands to monitor my server, only to find a drastic decrease in FSYNC/second values, which now gives back a value oscillating between 23 - 40 .
Also the PROXMOX status shows a high IOWAIT (I recall IOWAIT being virtually ZERO before things started going down the hill).
I did my resarch, and I found out that HARDWARE RAID1 cards do not pass through the TRIM commands that LINUX may be sending, so you should entirely depend on the internal garbage collection capabilities of the SSD itself. Which actually usually triggers when the SSD is "iddle" (which won't happen under "proxmox hammering" even with one virtual machine).
Hence, I realized that my SSD RAID1 is having a bad time consolidating free space whenever PROXMOX asks for a write operation. Maybe I am wrong. I would like very much if anyone wants me to provide more information, or perform some tests ...
I am trying to make my dedicated server provider to change the raid1 disks into INTEL S3700 which seems to be much more resilient to write operations, and also got a better garbage collection system, that -if I understood correctly- is constantly running in the background (does not wait for the SSD to be "iddle" to perform it's magic).
Also, it may be a "heads up" for SSD / RAID1 guys ... specially if those arrays have been stuffed with "desktop graded" SSDs, like the INTEL 520 series, which is my case. It may take months, or over a year, but IOWAIT will catch ya!
