Hello, Thanks for your responses. The issue appears to be somewhere beyond iSCSI. I just tried to do some "dd" tests locally on the storage server and I'm getting very low write speeds:
root@storage:/root# dd if=/dev/vg0/isoimages of=isoimages.vg0 62914560+0 records in 62914560+0 records out 32212254720 bytes (32 GB) copied, 945.573 s, 34.1 MB/s root@storage:/root# (/dev/vg0/isoimages is local LV to the storage server) So will have to find out what's the problem or bottleneck somewhere else. Load average on storage server is 4.0-5.0 for the following CPU according to lscpu output: Model name: Intel(R) Xeon(R) CPU E3-1230 v5 @ 3.40GHz Stepping: 3 CPU MHz: 800.000 CPU max MHz: 3401.0000 CPU min MHz: 800.0000 Could this be due to low (800.000 MHz) CPU frequency? Thanks! On 07/19/2017 10:03 AM, Eneko Lacunza wrote: > El 19/07/17 a las 08:41, Dietmar Maurer escribió: >>> So I cannot figure out why LVM-over-iSCSI is so slow. >> I guess your benchmark is simply wrong. You are testing the >> local cache, because you do not sync the data back to the storage. > Really, 2.7GB/s for 4x4TB disks in RAID10 seems totally unreasonable (I > guess they're not SSD drives...) > > I think that in the best conditions that could give about 200-250MB/s > max, totally sequential writes, etc. > > Don't know why iSCSI is so slow, have you checked CPU usage on both sides? > > Anyhow your test copy is too small, use a file that at least is double > the available RAM on storage server, or otherwise force sync. > > Cheers > Eneko > _______________________________________________ pve-user mailing list [email protected] https://pve.proxmox.com/cgi-bin/mailman/listinfo/pve-user
