[DRBD-user] Performance problem on drbd8 2-node cluster

Marco Marino marino.mrc at gmail.com
Mon May 6 14:12:20 CEST 2019

Thank you Gianni.
I tried to ask on the mailing list first because if I try to write on the
backing device, probably I need to resync drbd device when the cluster goes
up again.
Anyway, I will send tests on /dev/sdb as soon as possible.
Thank you

Il Lun 6 Mag 2019, 13:20 Gianni Milo <gianni.milo22 at gmail.com> ha scritto:

> I would do same tests on the backing storage first, without drbd, cluster
> management or any other complexity involved. Then after confirming that
> there's no any kind of bottleneck there, I would slowly move to the "upper
> layers" ...
> On Mon, 6 May 2019 at 09:49, Marco Marino <marino.mrc at gmail.com> wrote:
>> Hello, I'm using drbd 8.4.11 on a two node cluster on top of centos 7.
>> Both servers have the same hardware configuration: same cpu, ram,
>> disks,...More precisely there is a Megaraid lsi SAS 9361-8i with a raid5
>> volume. CacheCade is enabled for both controllers and I have a raid0 volume
>> with 4x256GB SSD disks.
>> I'm trying to do same test with fio:
>> fio --filename=/dev/mapper/vg1-vol2 --direct=1 --rw=randrw
>> --refill_buffers --norandommap --randrepeat=0 --ioengine=libaio --bs=16k
>> --rwmixread=30 --iodepth=32 --numjobs=32 --runtime=60 --group_reporting
>> --name=16k7030test
>> On node 1 I have:
>> Run status group 0 (all jobs):
>>    READ: bw=259MiB/s (272MB/s), 259MiB/s-259MiB/s (272MB/s-272MB/s),
>> io=15.2GiB (16.3GB), run=60021-60021msec
>>   WRITE: bw=605MiB/s (635MB/s), 605MiB/s-605MiB/s (635MB/s-635MB/s),
>> io=35.5GiB (38.1GB), run=60021-60021msec
>> I'm doing the test after this command:
>> pcs cluster standby  --> on node 2. So, there are no write through the
>> replication network and I can test the effective speed of the disk
>> if I try to do the same thing from node2 I have a degraded performance:
>> Run status group 0 (all jobs):
>>    READ: bw=101MiB/s (105MB/s), 101MiB/s-101MiB/s (105MB/s-105MB/s),
>> io=6039MiB (6332MB), run=60068-60068msec
>>   WRITE: bw=234MiB/s (245MB/s), 234MiB/s-234MiB/s (245MB/s-245MB/s),
>> io=13.7GiB (14.7GB), run=60068-60068msec
>> Someone can give me an advice? Why this happens? I repeat: there is the
>> same configuration on both servers. I can check any parameter and I can
>> give more details if needed.
>> Thank you
>> _______________________________________________
>> drbd-user mailing list
>> drbd-user at lists.linbit.com
>> http://lists.linbit.com/mailman/listinfo/drbd-user
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