[pve-devel] ceph firefly in pve repos

[Stefan Priebe - Profihost AG]

Am 11.09.2014 um 12:00 schrieb Dietmar Maurer:
>> yes dsync does a flush after each write of a bs. This is awfully slow.
>> You can, if you include my kernel patch skip this for SSDs with capicitors as they
>> should write the data down even in case of a power failure.
> 
> I thought that would be handled by the SSD drive internally? If there is a capicitor, the SSD can
> acknowledge the write immediately (write back cache)?

Some do and some do not. It depends on the firmware and the drive.

For example the intel 520 drives ignored the command even they do NOT
have a capicitor.

Intel S3700 do not ignore the command but they have a capicitor.

> Please can you point me to your patch? (do you have a link)

http://lists.ceph.com/pipermail/ceph-users-ceph.com/2013-November/035707.html

Stefan