NAS

[Maurice Hilarius]

>Where you said,Dan:

>Date: Wed, 03 Jul 2002 08:37:20 -0500
>From: Dan Yocum <yocum at fnal.gov>
>Subject: Re: NAS
>Organization: Fermilab
>
>Sorry to be a Johnny-come-lately to the discussion, but I noticed in the
>ALINKA clustering newsletter that you were discussing something very near
>and dear to my heart: big, cheap RAID arrays.
>
>I've "built" (read as, spec'ed out and had someone else build) 14 large NAS
>boxes for the Sloan Digital Sky Survey here at Fermilab, which totals about
>19TB right now.  That number will grow to about 50TB by the time our survey
>is done.  The CDF experiment just bought ~32TB in 15 boxes.  These all have
>3ware cards and big IDE disks, and you can't be 'em as far as
>bang-for-the-buck goes.  Final price is about half a penny per megabyte and
>they scream - ~100MB/s writes and >200MB/s reads.
>
>Anyway, I wrote up my experiences in a technical note here:
>http://home.fnal.gov/~yocum/storageServerTechnicalNote.html
>
>Cheers,
>Dan

Hi Dan.
You might want to try this:
With the 3Ware cards, install Linux software RAID.
We get write performance up to twice as fast this way, and can use 2 of the 
3Ware's to make on RAID of up to 24 disks, or, using current Maxtor 160GB 
drives, 3TB net capacity.
Using the Maxtor 160's we get RAID5 writes of 85-90MB sec, and reads over 
160MB/sec.
With RAID0 we could go much faster, but that is a bit fragile.
If one drive fails out your whole RAID set is toast.
Note that is with the Maxtor drives that are only 5400rpm.
With faster/larger drives like the new Western Digital 200GB/7200rpm model 
early bench tests are showing us RAID5 writes of over 110MB/sec on a 16 
drive, 2.9TB RAID array.
Reads are over 200MB/sec as well.
One comment was made about the i860 chipset limiting bus speed on PCI. 
While this is a very real problem with i860, the 3Ware cards are 64 
bit/33MHz, so can't move data substantially faster than this in any case. 
Later, when they ship a 66MHz or PCI-X card we expect this to change.

BTW< using NFS3, on a dual AthlonMP board, we get much better NFS transfer 
rates than is mentioned in this web page. Probably the P3 coppermines are 
the bottleneck here, or the boards memory bandwidth..



With our best regards,

Maurice W. Hilarius       Telephone: 01-780-456-9771
Hard Data Ltd.               FAX:       01-780-456-9772
11060 - 166 Avenue        mailto:maurice at harddata.com
Edmonton, AB, Canada      http://www.harddata.com/
    T5X 1Y3

2.3TB RAID5 NAS server - dual AthlonMP CPU, Linux, $10,995 CAD / $6850 USD