On Mon, Jun 7, 2010 at 9:54 PM, Ian Dall <ian@beware.dropbear.id.au> wrote:
quoted text
> On Mon, 2010-06-07 at 15:14 -0400, Bill Davidsen wrote:
>> Actually playing with that now. I got an Intel SATA 40GB SSD, and I am
>> trying various combinations of things to put on it. One thing which I
>> hoped would benefit was to put a f/s journal on SSD and then use the
>> option to push all through the journal (data=journal) in hopes that it
>> would then free the RAM needed for cache and thus speed operation.
>>
>> Since none of that has generated the performance I hoped,
>
> Interesting. If its the X25-V that you have, write performance is
> nothing to write home about even compared to a single hard drive, let
> alone a raid. By journaling data as well (as metadata), you just add
> extra write overhead, possibly even a new bottleneck.

Depends on whether you are talking about small, seeky writes or large
writes.  Even the X25-V will kill any rotating drive in small seeky
writes, but if you are trying to write big files faster than ~40MB/s,
the the rotating disk might win depending on the exact one you are
comparing it to.

quoted text
>> I also played with mirroring and write mostly, etc. Does provide a
>> general solution, at least in my tests.
>
> Do you mean "does NOT"?

write-mostly DOES work well in my tests...

-Dave
--
To unsubscribe from this list: send the line "unsubscribe linux-raid" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html