[DRBD-user] Mysql on DRBD: Cache Problem?

Mark Eisenblaetter mark.eisenblaetter at gmail.com
Fri Aug 1 17:14:15 CEST 2008


Hi,

ok i will look further into the drive cache.

But i found an MySQL option  sync_binlog if its set to 1
the failover is ok.

now i will look if i losst any data.


Thanks for your help
Mark

On Fri, Aug 1, 2008 at 4:51 PM, Lee Christie <Lee at titaninternet.co.uk>wrote:

>  Hi Mark
>
> we're talking about drive cache here, not raid adapter cache.
>
> 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.
>
> 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.
>
> 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.
>
>
>  ------------------------------
> *From:* Mark Eisenblaetter [mailto:mark.eisenblaetter at gmail.com]
> *Sent:* 01 August 2008 15:27
> *To:* Lee Christie
> *Cc:* drbd-user at lists.linbit.com
> *Subject:* Re: [DRBD-user] Mysql on DRBD: Cache Problem?
>
>  Hi Lee,
>
> it seems taht my P400i has no drivewritecache option.
> 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,
> so i hope in my p400i too.
>
> Mark
>
> On Fri, Aug 1, 2008 at 3:33 PM, Lee Christie <Lee at titaninternet.co.uk>wrote:
>
>>  Most hard drives ship with write-cache enabled.
>>
>> 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.
>>
>> Its possible your lost data was in hard drive cache.
>>
>>  ------------------------------
>> *From:* drbd-user-bounces at lists.linbit.com [mailto:
>> drbd-user-bounces at lists.linbit.com] *On Behalf Of *Mark Eisenblaetter
>> *Sent:* 01 August 2008 14:22
>> *To:* drbd-user at lists.linbit.com
>> *Subject:* [DRBD-user] Mysql on DRBD: Cache Problem?
>>
>>   Hi List,
>>
>> I'm trying to run a DRBDMySQL Cluster (Active/Passive) with Replication
>> for easier backup.
>>
>> My problem ist that after a hardkill from the master(Powerkill) the slave
>> misses binlog positions.
>>
>> After disable the Arraycontroller Write cache its reduced from 100k to 16k
>> Position but that not enough.
>>
>> I run DRBD with Protocal C and the minimal max-buffer of 32k.
>>
>> Is there any cache i miss? Or somthing else?
>>
>> Mark
>>
>>
>> setup: 2x HP DL360G5 whit raid 10 and Gigabit network for drbdsync only.
>>
>> --
>> Mark Eisenblätter
>> Geissendoerfer & Leschinsky GmbH
>> www.gl-sytemhaus.de
>>
>>  ------------------------------
>>
>> This email may contain legally privileged and/or confidential information.
>> It is solely for and is confidential for use by the addressee. Unauthorised
>> recipients must preserve, observe and respect this confidentiality. If you
>> have received it in error please notify us and delete it from your computer.
>> Do not discuss, distribute or otherwise copy it.
>>
>> Unless expressly stated to the contrary this e-mail is not intended to,
>> and shall not, have any contractually binding effect on the Company and its
>> clients. We accept no liability for any reliance placed on this e-mail other
>> than to the intended recipient. If the content is not about the business of
>> this Company or its clients then the message is neither from nor sanctioned
>> by the Company.
>>
>> We accept no liability or responsibility for any changes made to this
>> e-mail after it was sent or any viruses transmitted through this e-mail or
>> any attachment. It is your responsibility to satisfy yourself that this
>> e-mail or any attachment is free from viruses and can be opened without harm
>> to your systems.
>>
>>
>>
>
>
>
> --
> Mark Eisenblätter
> Geissendoerfer & Leschinsky GmbH
> www.gl-sytemhaus.de
>
>  ------------------------------
>
> This email may contain legally privileged and/or confidential information.
> It is solely for and is confidential for use by the addressee. Unauthorised
> recipients must preserve, observe and respect this confidentiality. If you
> have received it in error please notify us and delete it from your computer.
> Do not discuss, distribute or otherwise copy it.
>
> Unless expressly stated to the contrary this e-mail is not intended to, and
> shall not, have any contractually binding effect on the Company and its
> clients. We accept no liability for any reliance placed on this e-mail other
> than to the intended recipient. If the content is not about the business of
> this Company or its clients then the message is neither from nor sanctioned
> by the Company.
>
> We accept no liability or responsibility for any changes made to this
> e-mail after it was sent or any viruses transmitted through this e-mail or
> any attachment. It is your responsibility to satisfy yourself that this
> e-mail or any attachment is free from viruses and can be opened without harm
> to your systems.
>
>
>



-- 
Mark Eisenblätter
Geissendoerfer & Leschinsky GmbH
www.gl-sytemhaus.de
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.linbit.com/pipermail/drbd-user/attachments/20080801/6ab3fc71/attachment.htm 


More information about the drbd-user mailing list