Disk performance

hintalo68

New Member
Feb 6, 2024
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Hi Everybody

I have a debian 12 with 6.1.0-25 kernel. The hardware is HP dl380 g9 .
On the native linux kernel I have run this test three times.
sysbench fileio --file-total-size=5G prepare
The results was these.
917.16 MiB/sec
937.52 MiB/sec
934.25 MiB/sec

After that I have installed proxmox enviroment with 6.8.12-1-pve kernel, and run again the test.
The result was these.
621.06 MiB/sec
596.09 MiB/sec
594.96 MiB/sec

Why did the io speed drop so much , after installed proxmox ?
Thank
 
The hardware inside your HP dl380 g9 is what in # of disk(/s ?) and setup before and after install of pve ?
 
Pinne mal einen anderen kernel zum booten, der 6.8 is ein bisschen buggy.
 
So just think about what you messured before ... you have 5 disk in raid6 which means 3 disks netto as 2 are (rotating) write parity. Measured >300MB/s per 600GB sas hdd is unrealistic and your results are cache results in case of even write and read unrealistic while the "slow ~600MB/s" looks same also.
Don't know the specs for a 600GB hdd yet but if I assume 133MB/s that max out at 400MB/s sustained and all other is caching mechanism.
That does not mean that pve has a more bad caching than your debian before but it still doesn't make it more easy to compare which circumstances were activ to get that different results on same hardware. I would not trust on sysbench and even the ever best benchmark is "the real running application" for the host !!