Super slow performance on Proxmox SSD

Leon Roy

New Member
Mar 1, 2019
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We're evaluating Proxmox in our lab and have two setups - both running 5.3:

1. Xeon
Storage: ZFS (10x 3TB SAS + 100GB ZIL SSD)

2. i7-7700K
Storage: ext4 LVM (1x 1TB SATA SSD)

Running the following sysbench commands inside identical LXCs to evaluate storage performance:
sysbench --test=fileio --file-total-size=64G prepare
sysbench --test=fileio --file-total-size=64G --file-test-mode=rndrw --max-time=300 --max-requests=0 run
sysbench --test=fileio --file-total-size=64G cleanup

Results in performance figures:

System 1:

Throughput:
read, MiB/s: 66.08
written, MiB/s: 44.05

System 2:
Throughput:
read, MiB/s: 2.17
written, MiB/s: 1.45

When we ran VMware Workstation (on top of Windows 10) on System 2 our performance was 20x higher so pretty sure it's not a BIOS or system build issue:
Throughput:
read, MiB/s: 46.25
written, MiB/s: 30.83

Any ideas why a single SSD in Proxmox has such slow speeds?
 
LVM-thin.

We did run the test 3 times though and left the test files in place (ie. skipped sysbench cleanup) in case it was due to allocation latency.
 
LVM-thin.

We did run the test 3 times though and left the test files in place (ie. skipped sysbench cleanup) in case it was due to allocation latency.

Hi, don’t know if this was resolved, but since the underlying storage system is ZFS, lvm is most likely the issue.
You should stick to ZFS datasets instead of LVM as CoW on CoW would kill your performance.
 

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