Hardware Recommendations for LTSP

[Warren Togami]

----- Original Message -----
From: "Dusty" <dusty at sandust.com>
To: "Linux & Unix Advocates & Users" <luau at list.luau.hi.net>
Sent: Wednesday, May 09, 2001 7:27 AM
Subject: [luau] Re: Hardware Recommendations for LTSP


> To get anywhere near the theoretical max of ethernet you are going to need
better hardware than SMC, Linksys, or D-link.  They do offer some switches
with GIG ports, so you would need to look at the max throughput of the
entire switch to see if it will work for you.

Brian Chee at UH said about the same thing.  He actually suggested buying
HUBS instead of switches if all traffic is going to a single port, because
cheap switches tend to "crap out" under that kind of load.

>
> I have done channel bonding on Solairs (bonding 4 FE ports in a quad eth
card) connecting to Cisco instead of buying GIG ETH.  The problem was it was
very CPU intensive.  Sounds like you need to build a small lab and start
testing.  What hardware does LTSP recomend.   Maybe you should look at GIG
ETH for your server.
>

Yeah.  I'll determine if I need GIG ETH after testing.  I'm collecting a few
donated computers right now for some initial testing, but I need another 15.

> On the disk side, there is NO performance benefit of IDE RAID and some
performance hit for RAID 5.  You are just getting more size and some
protection.
>
> Dusty

Are you sure?  IDE RAID 0 can easily hit 55-70MB/sec thru-put on two 7200
rpm disks.  True that isn't redundant, but IDE RAID 5 (3 disk) can do about
45-55MB/sec.  IDE RAID lacks the onboard cache of *real* SCSI RAID
controllers, and CPU usage is much higher, but I think the cost/performance
tradeoff is worth it.  Most of the time I'm looking at this 1GHz CPU Linux
machine (with one disk), and the bottleneck always appears to be the disk
clicking away, with 5% CPU usage.  The LTSP servers will be dual 1GHz, so
I'm sure it can handle the extra overhead just fine.

With the cost savings over SCSI RAID, we could probably afford a Platypus
battery backed RAM drive.  350MB/sec Reiserfs journal.  Whoopass.