From: Anton Rommerskirchen <atr@atrsoft.de>
To: pgsql-performance@postgresql.org
Subject: Re: Contemplating SSD Hardware RAID
Date: Tue, 21 Jun 2011 20:29:26 +0200
Message-ID: <201106212029.26202.atr@atrsoft.de> (raw)
In-Reply-To: <4E0015F2.9060504@drivefaster.net>
References: <4E0015F2.9060504@drivefaster.net>
Am Dienstag, 21. Juni 2011 05:54:26 schrieb Dan Harris:
> I'm looking for advice from the I/O gurus who have been in the SSD game
> for a while now.
>
> I understand that the majority of consumer grade SSD drives lack the
> required capacitor to complete a write on a sudden power loss. But,
> what about pairing up with a hardware controller with BBU write cache?
> Can the write cache be disabled at the drive and result in a safe setup?
>
> I'm exploring the combination of an Areca 1880ix-12 controller with 6x
> OCZ Vertex 3 V3LT-25SAT3 2.5" 240GB SATA III drives in RAID-10. Has
> anyone tried this combination? What nasty surprise am I overlooking here?
>
> Thanks
> -Dan
Wont work.
period.
long story: the loss of the write in the ssd cache is substantial.
You will loss perhaps the whole system.
I have tested since 2006 ssd - adtron 2GB for 1200 Euro at first ...
i can only advice to use a enterprise ready ssd.
candidates: intel new series , sandforce pro discs.
i tried to submit a call at apc to construct a device thats similar to a
buffered drive frame (a capacitor holds up the 5 V since cache is written
back) , but they have not answered. so no luck in using mainstream ssd for
the job.
loss of the cache - or for mainstream sandforce the connection - will result
in loss of changed frames (i.e 16 Mbytes of data per frame) in ssd.
if this is the root of your filesystem - forget the disk.
btw.: since 2 years i have tested 16 discs for speed only. i sell the disc
after the test. i got 6 returns for failure within those 2 years - its really
happening to the mainstream discs.
--
Mit freundlichen Grüssen
Anton Rommerskirchen
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: pgsql-performance@postgresql.org
Cc: atr@atrsoft.de
Subject: Re: Contemplating SSD Hardware RAID
In-Reply-To: <201106212029.26202.atr@atrsoft.de>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox