[DRBD-user] ko-count and blocking backing devices

Roland Friedwagner r.friedwagner at gmail.com
Tue Feb 15 23:56:16 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.


As a second test I did the same with

version: 8.3.8 (api:88/proto:86-94)
GIT-hash: d78846e52224fd00562f7c225bcc25b2d422321d build by
root at drbd01.localdomain, 2011-02-15 22:51:22
 0: cs:Connected ro:Primary/Secondary ds:UpToDate/UpToDate C r----
    ns:32913 nr:0 dw:145 dr:2621481 al:2 bm:6 lo:0 pe:0 ua:0 ap:0 ep:1
wo:b oos:0

Hosted on two VirtualBox Centos5 Servers.

Writing with
dd if=/dev/urandom of=/mnt/t.dat bs=512 count=1 oflag=direct
seek=$RANDOM conv=notrunc &
some test records in a ext2 filesystem on top of /dev/drbd0.

This blocks when the LV backing device on secondary is suspended.

Same behavor: ko-count is ignored!

BTW: my dd examples in previous posts did use skip= but should also seek=
        So this is the explanation for the Concurrent write warnings,
because i've
        always written to the beginning of the device.



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