Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.
On 06/02/17 02:08 PM, Lazuardi Nasution wrote:
> Hi,
>
> I'm new with DRBD. I'm trying to setup dual primary nodes (VMs with
> virtio-net of bonded of dual 10GbE links) with following resource config.
>
> resource db {
> on db-1 {
> volume 0 {
> device /dev/drbd0 minor 0;
> disk /dev/vdc1;
> meta-disk internal;
> }
> address ipv4 10.10.130.9:7788
> <http://10.10.130.9:7788>;
> }
> on db-2 {
> volume 0 {
> device /dev/drbd0 minor 0;
> disk /dev/vdc1;
> meta-disk internal;
> }
> address ipv4 10.10.130.10:7788
> <http://10.10.130.10:7788>;
> }
> options {
> on-no-data-accessible io-error;
> }
> net {
> protocol C;
> allow-two-primaries yes;
> after-sb-0pri discard-zero-changes;
> after-sb-1pri discard-secondary;
> after-sb-2pri disconnect;
> sndbuf-size 1M;
> rcvbuf-size 2M;
> max-buffers 131072;
> max-epoch-size 20000;
> cram-hmac-alg sha1;
> shared-secret db;
> }
> disk {
> on-io-error detach;
> disk-flushes no;
> disk-barrier no;
> resync-rate 1G;
> al-extents 257;
> c-plan-ahead 8;
> c-fill-target 25M;
> c-max-rate 1G;
> c-min-rate 100M;
> }
> startup {
> wfc-timeout 30;
> outdated-wfc-timeout 20;
> degr-wfc-timeout 30;
> become-primary-on both;
> }
> }
>
>
> I have tried to change some of variables, but no matter I have done, the
> performance is just around 70MB/s like dd result below.
>
> [root at db-1 ~]# dd if=/dev/zero of=/dev/drbd0 bs=4194304 count=1000
> 1000+0 records in
> 1000+0 records out
> 4194304000 bytes (4.2 GB) copied, 61.7918 s, 67.9 MB/s
>
>
> The same test to the backing storage can give aroud 700MB/s performance.
> What should I do with this case?
>
> Best regards,
There are a few things here;
1. DRBD has sensible defaults. Start by dramatically simplifying your
config to only the specifics you need. Tune later after you have a
baseline. You'll find, I suspect, your tuning won't change much, or
often actually hurt performance.
2. Your test is flawed because dd uses caching unless you specify dsync.
Set that and also use a larger write file (I'd recommend minimum of 2x RAM).
3. You need to also test the network connection between the two nodes.
Use sperf or similar to ensure you are actually getting the network link
speed you expect.
--
Digimer
Papers and Projects: https://alteeve.com/w/
"I am, somehow, less interested in the weight and convolutions of
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have lived and died in cotton fields and sweatshops." - Stephen Jay Gould