[CentOS] SSD for Centos SWAP /tmp & /var/ partition

Mon May 23 18:01:54 UTC 2011
Rudi Ahlers <Rudi at SoftDux.com>

On Sun, May 22, 2011 at 12:29 AM, yonatan pingle
<yonatan.pingle at gmail.com> wrote:
> Hi Keith
> not sure about OCZ reliability for production , but i can confirm
> Intel x-25 drives work great with centos ( about 11 month's now ).
> I use two drives as /var in md mirror , using it for SQL and logs -
> it's an amazing boost vs ordinary drives.
> if you use the SSD for swap, don't put anything important on them, I
> have managed to destroy a drive which was used for heavy swap
> operations.
> (insane experiment with KVM virtual machines got to that situation ).
> the machines used the drive as RAM. ( that was an intel drive! ).
> I did experience a bad OCZ drive in the past, that's the reason i gone
> for the intel disks instead for production.
> the OCZ one died from normal usage on a laptop as a single drive.
> the intels might be slower then other SSD drives, but i find them to
> be very reliable in contrast for normal (sane) usage.

ZFS can use a SATA, SAS or SSD drive as cache drive to speed up common
reads & writes. I have seen some small improvements even when using a
cheaper grade SATA & SAS drive (as part of an experiment). The speed
improvement is quite a bit more evident on larger storage arrays.

You could also use 2 cheaper MLC type SSD's, one in a "cold standy"
type setup - where it's already in mounted in the server and then you
simply tell ZFS to stop using SSD1, and start using SSD2 instead.

15K SAS drives also add some level of improvement if you need speed  +
reliability on a tight budget.

Now, the question is, is is there any way to tell EXT3/4 to use a
separate drive as a cache drive for the same purpose? OR, how about
telling CentOS to use a separate drive for caching purposes in the
same way?

Kind Regards
Rudi Ahlers

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