You may try to disable dynamic sync rate by setting "c-plan-ahead" to 0 and increase "max-buffers". That's the only way which helped me to get reasonable sync rate with 100GigE connection.
net { ... max-buffers 32K; # max-epoch-size 18K; } disk { ... c-plan-ahead 0; } You can find some more info here: https://serverfault.com/questions/740311/drbd-terrible-sync-performance-on-10gige/740370 //OE -----Original Message----- From: Adam Weremczuk <ad...@matrixscience.com> To: drbd-user@lists.linbit.com Subject: [DRBD-user] slow sync speed Date: Wed, 10 Oct 2018 14:57:02 +0100 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/drbdversion: 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 KBAccess policy: RWRead policy: NormalWrite policy: Write Back with BBUIO policy: DirectDrive Cache: DisableDisable 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. It seems to be a problem with default DRBD settings. Can anybody recommend optimal tweaks specific to my environment? Regards,Adam _______________________________________________drbd-user mailing listdrbd-user@lists.linbit.comhttp://lists.linbit.com/mailman/listinfo/drbd-user
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