[DRBD-user] How long does it take OOS to clear
gcstang at gmail.com
Mon Oct 21 19:31:12 CEST 2019
Would any of these values being changed help or would it need to be the
actual speed between the two nodes that needs to be increased?
On Mon, Oct 21, 2019 at 10:10 AM Digimer <lists at alteeve.ca> wrote:
> I assumed it wasn't paused, but that confirms it.
> Protocol A allows for out of sync to grow. It says "when the data in on
> the network buffer to send to the peer, consider the write complete". As
> such, data that hasn't made it over to the peer causes oos to climb. If
> you have a steady write rate that is faster than your transmit
> bandwidth, then seeing fairly steady OOS makes sense.
> To "fix" it, you need to increase the connection speed to the peer node.
> Or, less likely, if the peer's disk is slower than the bandwidth
> connecting it, speed up the disk write speed.
> In either case, what you are seeing is not a surprise, and it's not a
> problem with DRBD. The only other option is to use protocol C, so that a
> write isn't complete until it reaches the peer, but that will slow down
> the write performance of the primary node to be whatever speed you have
> to the peer. That's likely unacceptable.
> In short, you have a hardware/resource issue.
> On 2019-10-21 12:19 p.m., G C wrote:
> > version: 8.4.10
> > Ran the resume-sync all and received:
> > 0: Failure: (135) Sync-pause flag is already cleared
> > Command 'drbdsetup-84 resume-sync 0' terminated with exit code 10
> > Protocol used is 'A', our systems are running on a cloud environment.
> > On Mon, Oct 21, 2019 at 9:09 AM Digimer <lists at alteeve.ca
> > <mailto:lists at alteeve.ca>> wrote:
> > 8.9.2 is the utils version, what is the kernel module version?
> > (8.3.x/8.4.x/9.0.x)?
> > It's possible something paused sync, but I doubt it. You can try
> > 'drbdadm resume-sync all'. The oos number should change constantly,
> > time a block changes it should go up and every time a block syncs it
> > should go down.
> > What protocol are you using? A, B or C?
> > digimer
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