[DRBD-user] Online Verify Seems Really Slow

Lionel Sausin ls at numerigraphe.com
Fri Jun 1 17:37:24 CEST 2012

Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.

Looks like you're using adaptative syncer rate, so verify will be 
throttled when applications request I/O. You may tune c-min-rate if it's 
OK for you to slow down applications.
During the initial sync, maybe that didn't happen because you simply 
didn't have any application I/O going on.

Another wild guess: you don't seem to use a csums-alg, so maybe you CPU 
is simply too weak to make a realtime MD5 digest of all the data.
In "top", that would be visible by drbdX_worker using >90% of one core.
In that case you could try a faster digest algorithm like crc32.

Lionel Sausin.

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