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

Tue May 24 11:06:04 UTC 2011
Michael Simpson <mikie.simpson at gmail.com>

On 23 May 2011 11:04, John Hodrien <J.H.Hodrien at leeds.ac.uk> wrote:
> On Mon, 23 May 2011, Rudi Ahlers wrote:
>> Doesn't SATA and SAS drives also wear out?
> Not in such a clear way related to usage.  You could have a SATA disk that you
> write to 24 hours a day and it could last for years.  With an SSD, you'd be
> certain to kill your disk in months if you treated it like that.
> On the other hand, I'd imagine an SSD used for solely reads could last a
> *very* long time.

i have been using an 8GB PATA interface SSD (mlc) for *years* now as
the sole disc on a laptop running centos for several hours on a daily
basis. Other than a noticeable slowdown once it got to the point of
having to do the erase before write (that TRIM would alleviate though
not on this drive) it is still way faster than the spinning drive it
replaced. This laptop (Dell Latitude L400) also has only 256MB of RAM
and runs a desktop so swap is used an awful lot. I now have a lot of
SSDs in production and have only seen spinning discs go bad for no
real reason (especially WD 3.5inch and hitachi 2,5inch for some
reason) whereas the SSDs have been rock solid. Either i am just lucky
or maybe the guys that were recommending several years ago using SSDs
for the zil in super large ZFS disc storage setups were correct. :)

Pretty soon extra large storage will be flash on PCIe -> SSD
->spinning discs as the data ages. Quite where it will then go to for
really long term i'm not sure ?tape ?cloud.

I can heartily recommend moving to SSD for OS / swap / cache / db
especially when CentOS 6 comes out
-though in order to use TRIM on non-swap partitions you will need to
be using ext4 (no LVM) and have the discard option set.