[PVE-User] LVM over ISCSI Bad performance

Michael Rasmussen mir at miras.org
Tue Jun 21 19:48:47 CEST 2016


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Multipath must be manually configured via CLI.

On June 21, 2016 7:44:39 PM GMT+02:00, Harald Leithner <leithner at itronic.at> wrote:
>Hi again^^,
>
>I miss interpreted the benchmark result, with writeback cache is 5500
>MB/s so thats ok... with direct IO it gets about 100 MB/s
>
>But I have still no clue how I could use multipath with proxmox web
>interface.
>
>regards,
>
>Harald
>
>Am 21.06.2016 um 19:15 schrieb Harald Leithner:
>> Hi,
>>
>> I have a MSA2312 connected with 1gbit to a 3 node PVE 4.2 Cluster.
>> I managed to get ISCSI and LVM working and attached it to a VM.
>>
>> Atm I didn't manage to get multipath working with PVE because the
>> Wikipage tells me how to create multipath (which works) but not how
>PVE
>> uses it for LVM VGs... maybe someone give me a hint.
>>
>> Anyway the main problem is that fio only gives me a read performance
>of
>> 5 mb/s if I attach a disk as virtio or scsi device with cache
>"Writeback".
>>
>> If I attach the same SAN Drive directly in the VM with iSCSI (with
>and
>> without multipath) I get about 112 MB/s.
>>
>> I also get this speed on the pve host.
>>
>> I use:
>>
>> fio --filename=/dev/sdb --direct=1 --rw=read --bs=1m --size=20G
>> --numjobs=200 --runtime=60 --group_reporting --name=file1
>>
>> for benchmarking.
>>
>> While benchmarking the VM I see 1300% cpu usage on the host (mainly
>sys
>> time)
>>
>> Maybe someone has a idea?
>>
>> regards
>>
>
>--
>Harald Leithner
>
>ITronic
>Wiedner Hauptstra├če 120/5.1, 1050 Wien, Austria
>Tel: +43-1-545 0 604
>Mobil: +43-699-123 78 4 78
>Mail: leithner at itronic.at | itronic.at
>_______________________________________________
>pve-user mailing list
>pve-user at pve.proxmox.com
>http://pve.proxmox.com/cgi-bin/mailman/listinfo/pve-user

- --
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