recommend a disk setup for LTSP install?

Steve Rippl rippls at
Wed Mar 31 03:09:10 BST 2010

john wrote:
> Hi all,
> I have come to the conclusion that my single 7k sata disk is too slow to serve
> 25 plus LTSP thin clients. I see high disk writes accompanied by high
> CPU wait time.
> My mobo supports SAS. I am wondering what the optimal disk setup is
> with regard to speed. Can I get
> away with a single 10-15K SAS drive or should I be looking to setup
> raid 5, 6, or 10? How about
> two disks, a sata for the OS and a fast SAS for /home/ /tmp ?
> I'd appreciate some advice!
> Thanks!
> John
I guess it depends on what you need in terms of redundancy versus 
maximizing available disk space versus speed!  For max speed (and no 
redundancy) use a pair of stripped (RAID 0) sas drives.  Use 2 such 
pairs (one for the os, one for /home) for even better performance...

On our LTSP servers we use 2 pairs of RAID 1 sata drives (might be 10k 
rather then 7k), one pair for os, one for /home folders.  That works 
well enough, redundancy and some speed gains (faster reads, slightly 
faster write) and no load due to IO wait that I've seen. 

You don't want RAID 5 or 6 if you want speed.

We only use sas drives on our virtual server hosts (along with RAID 10) 
where we're really looking for high speed raid arrays.

The bottom line is I don't think you need to pay for sas for LTSP, you 
can buy 2 sata drives for less than one sas, mirror them, get redundancy 
and plenty of performance (or strip them if you don't care about 
redundancy to get even more speed, but wouldn't you want your server to 
keep working if one drive failed?)


Steve Rippl
Technology Director
Woodland Public Schools
360 225 9451 x326

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