Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.
Thanks for the write up y'll. I'll have to think about #3 not sure I grasp it fully.
Last night I started a 12 TB test and started first initialization for observation (0 is primary).
I have node0:eth1 wired directly into node1:eth1 with 10 foot CAT 6 cable (MTU=9000)
Data from node1 to node0
PING 10.10.52.232 (10.10.52.232) 8970(8998) bytes of data.
8978 bytes from 10.10.52.232: icmp_seq=1 ttl=64 time=0.316 ms
This morning's progress report from node1:(drbd v8.4.5)
[===>................] sync'ed: 21.7% (8847740/11287100)M
finish: 62:50:50 speed: 40,032 (39,008) want: 68,840 K/sec
which confuses me: 8.8M out of 11.3M is 77.8% synced, not? I will let this test finish before I do a dd attempt.
iostat reveals %idle cpu 99%+ and little to no %iowait (near 0%), iotop confirms very little IO (<5 K/s), typical data
Device: rrqm/s wrqm/s r/s w/s rsec/s wsec/s avgrq-sz avgqu-sz await svctm %util
sdb1 0.00 231.00 0.00 156.33 0.00 79194.67 506.58 0.46 2.94 1.49 23.37
Something is throttling this IO as 40M/s is about half of what I was hoping for. Will dig some more.
-Henk
________________________________________
From: drbd-user-bounces at lists.linbit.com [drbd-user-bounces at lists.linbit.com] on behalf of Philipp Reisner [philipp.reisner at linbit.com]
Sent: Thursday, October 23, 2014 9:17 AM
To: drbd-user at lists.linbit.com
Subject: Re: [DRBD-user] drbd storage size
Am Donnerstag, 23. Oktober 2014, 08:55:03 schrieb Digimer:
> On 23/10/14 04:00 AM, Philipp Reisner wrote:
> > 2a) Initialize both backend devices to a known state.
> >
> > I.e. dd if=/dev/zero of=/dev/sdb1 bs=$((1024*1024)) oflag=direct
>
> Question;
>
> What I've done in the past to speed up initial sync is to create the
> DRBD device, pause-sync, then do your 'dd if=/dev/zero ...' trick to
> /dev/drbd0. This effectively drives the resync speed to the max possible
> and ensures full sync across both nodes. Is this a sane approach?
>
Yes, sure that is a way to do it. (I have the impression that is something
form the drbd-8.3 world.)
I do not know from the top of the head if that will be faster than the
built-in background resync in drbd-8.4.
Best,
Phil
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