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<DIV align=left><SPAN class=093004714-01082008><FONT face=Arial color=#0000ff size=2>Hi Mark</FONT></SPAN></DIV>
<DIV align=left><SPAN class=093004714-01082008><FONT face=Arial color=#0000ff size=2></FONT></SPAN> </DIV>
<DIV align=left><SPAN class=093004714-01082008><FONT face=Arial color=#0000ff size=2>we're talking about drive cache here, not raid adapter
cache.</FONT></SPAN></DIV>
<DIV align=left><SPAN class=093004714-01082008><FONT face=Arial color=#0000ff size=2></FONT></SPAN> </DIV>
<DIV align=left><SPAN class=093004714-01082008><FONT face=Arial color=#0000ff size=2>on SCSI/SATA drives the cache is typically a jumper or a
firmware setting that has to be changed via a manufacturer utility. On the later
SAS drives it is software controllable through your raid adapter provided that
your vendor has implemented the functionality.</FONT></SPAN></DIV>
<DIV align=left><SPAN class=093004714-01082008><FONT face=Arial color=#0000ff size=2></FONT></SPAN> </DIV>
<DIV align=left><SPAN class=093004714-01082008><FONT face=Arial color=#0000ff size=2>By default raid adapters have writethrough cache ON and
writeback cache OFF - unless you have a battery backup unit in which case the
default will be writeback ON.</FONT></SPAN></DIV>
<DIV align=left><SPAN class=093004714-01082008><FONT face=Arial color=#0000ff size=2></FONT></SPAN> </DIV>
<DIV align=left><SPAN class=093004714-01082008><FONT face=Arial color=#0000ff size=2>After the defaults anything is possible. The cards we use
are set to use writeback with BBU, but if a drive fails the card switches to
writethrough for additional security.</FONT></SPAN></DIV>
<DIV align=left><SPAN class=093004714-01082008><FONT face=Arial color=#0000ff size=2></FONT></SPAN> </DIV><BR>
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<FONT face=Tahoma size=2><B>From:</B> Mark Eisenblaetter
[mailto:mark.eisenblaetter@gmail.com] <BR><B>Sent:</B> 01 August 2008
15:27<BR><B>To:</B> Lee Christie<BR><B>Cc:</B>
drbd-user@lists.linbit.com<BR><B>Subject:</B> Re: [DRBD-user] Mysql on DRBD:
Cache Problem?<BR></FONT><BR></DIV>
<DIV></DIV>
<DIV>Hi Lee,<BR><BR>it seems taht my P400i has no drivewritecache
option.<BR>Wenn i try to modify it comes up whit an error. And in one document
i fount that it's default of in P800 controllers,<BR>so i hope in my p400i
too.<BR><BR>Mark<BR><BR>
<DIV class=gmail_quote>On Fri, Aug 1, 2008 at 3:33 PM, Lee Christie
<SPAN><<A href="mailto:Lee@titaninternet.co.uk">Lee@titaninternet.co.uk</A>></SPAN>
wrote:<BR>
<BLOCKQUOTE class=gmail_quote style="PADDING-LEFT: 1ex; MARGIN: 0pt 0pt 0pt 0.8ex; BORDER-LEFT: rgb(204,204,204) 1px solid">
<DIV>
<DIV align=left><SPAN><FONT face=Arial color=#0000ff size=2>Most hard drives
ship with write-cache enabled.</FONT></SPAN></DIV>
<DIV align=left><SPAN><FONT face=Arial color=#0000ff size=2></FONT></SPAN> </DIV>
<DIV align=left><SPAN><FONT face=Arial color=#0000ff size=2>When using
decent raid controllers its best to turn off the write(back) cache on hard
drives. In our testing it makes no difference anyway with a good
card.</FONT></SPAN></DIV>
<DIV align=left><SPAN><FONT face=Arial color=#0000ff size=2></FONT></SPAN> </DIV>
<DIV align=left><SPAN><FONT face=Arial color=#0000ff size=2>Its possible
your lost data was in hard drive cache.</FONT></SPAN></DIV><BR>
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<HR>
<FONT face=Tahoma size=2><B>From:</B> <A href="mailto:drbd-user-bounces@lists.linbit.com">drbd-user-bounces@lists.linbit.com</A>
[mailto:<A href="mailto:drbd-user-bounces@lists.linbit.com">drbd-user-bounces@lists.linbit.com</A>]
<B>On Behalf Of </B>Mark Eisenblaetter<BR><B>Sent:</B> 01 August 2008
14:22<BR><B>To:</B> <A href="mailto:drbd-user@lists.linbit.com">drbd-user@lists.linbit.com</A><BR><B>Subject:</B>
[DRBD-user] Mysql on DRBD: Cache Problem?<BR></FONT><BR></DIV>
<DIV>
<DIV></DIV>
<DIV class=Wj3C7c>
<DIV></DIV>
<DIV>Hi List,<BR><BR>I'm trying to run a DRBDMySQL Cluster
(Active/Passive) with Replication for easier backup.<BR><BR>My problem ist
that after a hardkill from the master(Powerkill) the slave misses binlog
positions.<BR><BR>After disable the Arraycontroller Write cache its
reduced from 100k to 16k Position but that not enough.<BR><BR>I run DRBD
with Protocal C and the minimal max-buffer of 32k.<BR><BR>Is there any
cache i miss? Or somthing else?<BR><BR>Mark<BR><BR><BR>setup: 2x HP
DL360G5 whit raid 10 and Gigabit network for drbdsync only.
<BR><BR>-- <BR>Mark Eisenblätter<BR>Geissendoerfer & Leschinsky
GmbH<BR><A href="http://www.gl-sytemhaus.de">www.gl-sytemhaus.de</A><BR></DIV></DIV></DIV></BLOCKQUOTE></DIV><FONT face=Tahoma size=2><FONT color=#0000ff>
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<P align=left><FONT face=Tahoma color=#0000ff size=2></FONT> </P></BLOCKQUOTE></DIV><BR><BR><BR>-- <BR>Mark
Eisenblätter<BR>Geissendoerfer & Leschinsky GmbH<BR><A href="http://www.gl-sytemhaus.de">www.gl-sytemhaus.de</A><BR></DIV></BLOCKQUOTE></BODY><!--[object_id=#titaninternet.co.uk#]--><FONT face=Tahoma size=2><FONT color=#0000ff>
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