Delaylog

[Stan Hoeppner]

Arkadiusz Miskiewicz put forth on 9/14/2010 2:06 PM:
> On Tuesday 14 of September 2010, Fabricio Archanjo wrote:
>> Hey all,
>>
>>    I just trying delaylog in my server that has a mysql database. When
>> i monted my /var/lib/mysql with delaylog option, it showed me:
>> "Enabling EXPERIMENTAL delayed logging feature - use at your own
>> risk". Ok, i know it's experimental, but what kind of problem could i
>> have using delaylog?
> 
> ... and what problems in case of system hang or power loss when compared to 
> nodelaylog mode?

This was covered in prior posts IIRC.  Delaylog holds more write
transactions in memory in an effort to decrease the amount of disk I/O
and optimize write patterns.  The more blocks waiting in the in memory
log, the more data will be lost due to power outage, controller/disk
failure, storage HBA/network failure (iSCSI/FC), kernel panics, etc.

Same failure modes as before, but with potentially greater loss of
data--unless there is an undiscovered bug that can wreck the entire
filesystem.  ;)  Which I believe is the reason for the "experimental"
boilerplate.

-- 
Stan