Re: Tunning - cache write (database)

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> I suggest you start by reading
> http://www.mail-archive.com/linux-btrfs@xxxxxxxxxxxxxxx/msg18827.html
>
> After that, PROBABLY start your database by preloading libeatmydata to
> disable fsync completely.

Which will cure the sympthoms, not the issue itself - I remember the
same advice was given for Reiser4 back then ;)
Usually for non-toy use-cases data is too valueable to just disable fsync.

- Clemens

2012/10/1 Fajar A. Nugraha <list@xxxxxxxxx>:
> On Mon, Oct 1, 2012 at 8:27 PM, Cesar Inacio Martins
> <cesar_inacio_martins@xxxxxxxxxxxx> wrote:
>
>> My problem:
>> * Using btrfs + compression , flush of 60 MB/s take 4 minutes....
>> (on this 4 minutes they keep constatly I/O of +- 4MB/s no disks)
>> (flush from Informix database)
>
>
>> * OpenSuse 12.1 64bits, running over VmWare ESXi 5
>> * Btrfs version : btrfsprogs-0.19-43.1.2.x86_64
>> * Kernel : Linux jdivm06 3.1.10-1.16-desktop #1 SMP PREEMPT Wed Jun 27
>
>
>> My question, what I believed will help to avoid this long flush :
>> * Have some way to force this flush all in memory cache and then use the
>> btrfs background process to flush to disk ...
>>   Security and recover aren't a priority for now, because this is part of a
>> database bulkload ...after finish , integrity will be desirable (not a
>> obligation, since this is a test environment)
>>
>> For now, performance is the mainly requirement...
>
>
> I suggest you start by reading
> http://www.mail-archive.com/linux-btrfs@xxxxxxxxxxxxxxx/msg18827.html
>
> After that, PROBABLY start your database by preloading libeatmydata to
> disable fsync completely.
>
> On a side note, zfs has "sync" property, which when set to "disabled",
> have pretty much the same effect as libeatmydata.
>
> --
> Fajar
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