Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.
On Mon, Sep 15, 2008 at 03:55:55PM +0300, Pan'ko Alexandr wrote: > Hi. > > Let's see article from > http://wiki.centos.org/HowTos/Ha-Drbd > > Let's do commands: > > [root at node1 /]# drbdadm primary repdata ; mount /dev/drbd0 /repdata > [root at node1 /]# dd if=/dev/urandom of=/repdata/test.file bs=1000000c > count=1000; ip l set eth0 down; how about dd ... conv=fsync see also: man fsync > [root at node1 /]# ls -l /repdata/test.file > -rw-r--r-- 1 user users 1000000000 Sep 15 15:07 /repdata/test.file thats all in page cache still. > [root at node2 /]# drbdadm primary repdata ; mount /dev/drbd0 /repdata > [root at node2 /]# ls -l /repdata/test.file > -rw-r--r-- 1 user users 868456004 Sep 15 15:07 /repdata/test.file > > As you will see there will be different sizes. > But they SHOULD be the same. > > If we will add to mount command the option '-o sync', than there will > be no differences in sizes. But in case of 'bs=1c' in dd command the > file creation will be very and very slow because of turned off chaching. > > Anybody knows this issue? > SHOULD I turn off caching om ALL underling devices and filesystems to > get HA cluster filesystem? -- : Lars Ellenberg : LINBIT | Your Way to High Availability : DRBD/HA support and consulting http://www.linbit.com DRBD® and LINBIT® are registered trademarks of LINBIT, Austria. __ please don't Cc me, but send to list -- I'm subscribed