Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.
On 2011-11-03 22:15, Nick Morrison wrote:
>
> On 3 Nov 2011, at 09:25, Florian Haas wrote:
>
>> Read the bullet list. Then start troubleshooting your network stack.
>> When you get "Digest integrity check FAILED" errors, you have every
>> reason _not_ to be sure the network is OK.
>
> I'm now finding myself a cable to connect these hosts directly.
That may or may not solve your issue; the original motivation for the
data integrity feature was to catch issues with NICs, not cables.
> Next question: can I now depend on my data being the same over both disks? Should I run an online verify? Or is the fact that it caught the problem and stopped enough to ensure integrity?
Let's put it this way: it's highly, highly unlikely that borked data
ended up on your disk, but you can run a verify anyway. Now, just so you
don't freak out needlessly when you do find out-of-sync sectors: verify
you still run into false positives, as explained at length here:
http://www.mail-archive.com/drbd-user@lists.linbit.com/msg03373.html
Have we mentioned storage replication is complicated? :)
> I would like to run a verify regularly, but I ran into a problem. I added the verify-alg parameter to the net section of my resource, but drbdadm complains when I adjust:
>
> net {
> cram-hmac-alg sha1;
> shared-secret avnerunvaadsf4n4nn4b4bnb4ai4jfaoi4hf;
> after-sb-0pri discard-zero-changes;
> after-sb-1pri discard-secondary;
> data-integrity-alg md5;
> verify-alg md5;
> }
>
> root at kvm-host-01:~# drbdadm adjust host1
> drbd.d/host1.res:22: Parse error: 'an option keyword' expected,
> but got 'verify-alg'
> root at kvm-host-01:~#
>
> I guess the syntax has changed. How do I enable this in Lucid's DRBD 8.3.7?
It belongs in the "syncer" section in 8.3.x.
http://www.drbd.org/users-guide-legacy/s-use-online-verify.html
Hope this helps,
Florian
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