[PVE-User] DRBD sync speed

Adam Weremczuk adamw at matrixscience.com
Wed Oct 10 15:34:21 CEST 2018


Yes, there must be something wrong with the defaults.

This seems to be a good starting point: 
https://serverfault.com/questions/740311/drbd-terrible-sync-performance-on-10gige/740370

It looks more complex than I expected.


On 10/10/18 14:27, Gilberto Nunes wrote:
> Hi
>
> I think this problem is related DRDB and not PVE!
>
> ---
> Gilberto Nunes Ferreira
>
> (47) 3025-5907
> (47) 99676-7530 - Whatsapp / Telegram
>
> Skype: gilberto.nunes36
>
>
>
>
>
> Em qua, 10 de out de 2018 às 10:23, Adam Weremczuk <adamw at matrixscience.com>
> escreveu:
>
>> Hi all,
>>
>> I'm trying out DRBD Pacemaker HA Cluster on Proxmox 5.2
>>
>> I have 2 identical servers connected with 2 x 1 Gbps links in bond_mode
>> balance-rr.
>>
>> The bond is working fine; I get a transfer rate of 150 MB/s with scp.
>>
>> Following this guide:
>> https://www.theurbanpenguin.com/drbd-pacemaker-ha-cluster-ubuntu-16-04/
>> was going  smoothly up until:
>>
>> drbdadm -- --overwrite-data-of-peer primary r0/0
>>
>> cat /proc/drbd
>> version: 8.4.10 (api:1/proto:86-101)
>> srcversion: 17A0C3A0AF9492ED4B9A418
>>    0: cs:SyncSource ro:Primary/Secondary ds:UpToDate/Inconsistent C r-----
>>       ns:10944 nr:0 dw:0 dr:10992 al:8 bm:0 lo:0 pe:0 ua:0 ap:0 ep:1 wo:f
>> oos:3898301536
>>       [>....................] sync'ed:  0.1% (3806932/3806944)M
>>       finish: 483:25:13 speed: 2,188 (2,188) K/sec
>>
>> The transfer rate is horribly slow and at this pace it's going to take
>> 20 days for two 4 TB volumes to sync!
>>
>> That's almost 15 times slower comparing with the guide video (8:30):
>> https://www.youtube.com/watch?v=WQGi8Nf0kVc
>>
>> The volumes have been zeroed and contain no live data yet.
>>
>> My sdb disks are logical drives (hardware RAID) set up as RAID50 with
>> the defaults:
>>
>> Strip size: 128 KB
>> Access policy: RW
>> Read policy: Normal
>> Write policy: Write Back with BBU
>> IO policy: Direct
>> Drive Cache: Disable
>> Disable BGI: No
>>
>> Performance looks good when tested with hdparm:
>>
>> hdparm -tT /dev/sdb1
>>
>> /dev/sdb1:
>>    Timing cached reads:   15056 MB in  1.99 seconds = 7550.46 MB/sec
>>    Timing buffered disk reads: 2100 MB in  3.00 seconds = 699.81 MB/sec
>>
>> The volumes have been zeroed and contain no live data yet.
>>
>> Any idea why the sync rate is so painfully slow and how to improve it?
>>
>> Regards,
>> Adam
>>
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>>
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