[DRBD-user] blocking I/O with drbd

Volker mail at blafoo.org
Fri Dec 16 15:48:33 CET 2011

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


>> What surprises me the most is the delay between the load rising and the
>> finished dd. a short timeline to make myself clear:
> To rid yourself of surprises, either pass the oflag=direct to dd or
> follow it by a call to `sync`.

We're getting there. Calling 'sync' right after dd (no oflag=direct)
takes forever and the load rises to 4-5.

$ dd if=/dev/zero of=./test-data.dd bs=4096 count=10240 && time sync
41943040 bytes (42 MB) copied, 0.113586 seconds, 369 MB/s
real	0m15.469s
user	0m0.001s
sys	0m0.055s

Now, how do i "debug" sync? :-)

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