Re: Data on NAS / NFS - Mailing list pgsql-general

From Hannes Dorbath
Subject Re: Data on NAS / NFS
Date
Msg-id 46AE0E54.2040605@theendofthetunnel.de
Whole thread Raw
In response to Data on NAS / NFS  (Jean-Denis Girard <jd.girard@sysnux.pf>)
List pgsql-general
On 28.07.2007 06:48, Jean-Denis Girard wrote:
> The NAS would be from LaCie, using 4 disks (Raid5 + spare)
> (http://www.lacie.com/fr/products/product.htm?pid=10876), mounted via
> NFS from a Linux server running Postgresql .

Sorry, but that sounds like a sick setup..

1.) RAID 5 is a bad choice for a DBMS, due to implicit reads caused by
parity calculation.
2.) Most cheap NAS (such as this one) have way to high latency for a DBMS.
3.) NFS is nothing you want to have a DBMS running on top.
4.) I don't think this device has battery backed cache.
5.) At least I have bad experiences with Lacie storage devices (Bigger
Disk Extreme)


To sum it up.. I'd say what you get with that setup is a dead slow,
unstable PostgreSQL experience with a good chance of data corruption on
  power failure.


--
Regards,
Hannes Dorbath

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