Re: Where to put the journal

[Edward Shishkin <edward@namesys.com>]

Vladimir V. Saveliev wrote:

> Hello
>
> Xuân Baldauf wrote:
>
>> Hello,
>>
>> I want to setup a Linux software RAID 5 over disks of different speed 
>> with reiserfs on top. I know that the journal has to be accessed 
>> frequently for comparably small accesses. That's why I'm considering 
>> to "offload" the journal onto an extra partition on a faster disk of 
>> the RAID set.
>>
>> Thus, the journal would not be protected by the RAID, but this is not 
>> so important for me.
>>
>> Is this kind of reasoning sane? Would there be any speedup by 
>> offloading the journal?
>>
>

Hello.
Unfortunately comprehensive results of journal relocation are obsolete
as it was done at the beginning of mongo evolution. As I remember there
were no any essential speedups. The only result of  journal  relocation that
was created by new mongo benchmark can be found here:
http://thebsh.namesys.com/benchmarks/journal_relocation_to_NVRAM.html

Edward.

> Person who did some tests on non standard journal is on vacation. He 
> is expected to come back today. Maybe he remembers benchmark results,
>
>
>