Re: sas fileserver

[Michael West <quagly@mitzit.net>]

On Fri, Jan 10, 2003 at 10:45:51AM +0000, Karsten M. Self wrote:
> on Tue, Jan 07, 2003 at 06:21:17PM -0800, Michael West (web@mitzit.net) wrote:
> > I have been asked to help with getting a server for SAS.  One of the
> > large expenses of this is the 200Gb+ RAID-5 disk on the EMC frame.
> > When presented with $$$$$ the question came, can't I just get
> > something I can put under my desk and save $$$$$? 
> > 
> > The SAS server will be on WIN2K.  I am thinking of using Debian with
> > software RAID and SAMBA.  I have had good experience with this.  Maybe
> > even use the 8mg cache western digital IDE drives.  We only expect a
> > dozen users simultaneous or so, but working with large datasets.  
> > 
> > I have never seen anything about the best configuration of a file
> > server with few connections and gobs of data being used per
> > connection.  
> > 
> > Does anyone have experience with something similar?  How will SAMBA
> > perform when hammered by SAS?   
> > 
> > For the purposes of this thread, let us assume that the maintenance,
> > service, backup and recovery and such is satisfactorily worked out.
> > They are the major problems, but I am looking for advice on just the
> > fileserver question.
> 
> Michael, a few suggestions.
> 
> I've done a lot of SAS work, most of it in my past.  I've also worked
> with GNU/Linux and some RAIDed filestorage, as well as Samba, more
> recently.  GNU/Linux and Samba should be more than robust enough for
> this purpose.
> 
> First, if what you're replacing is an EMC server, I'd suggest going
> whole-hog with GNU/Linux:  SCSI RAID beats software on performance, and
> IDE RAID on reliability.  The cost is higher by a significant fraction
> (more than double), but if this is your primary data store, that
> shouldn't be a hard sell.  200 GiB isn't all that big these days (you
> can buy single IDE drives with that capacity).  Focus on reliability and
> backups.  I've had very mixed results with 3Ware's Escalade products
> (5xxx, 6xxx, and 7xxx) over a couple of years.

     Thanks,
          The cost of a SCSI RAID adapter and SCSI vs. IDE disk is tiny compared
          to what we get charged to use the EMC.  
          
          Is there an adapter you would recommend?

> 
> SAS analysis usage is usually a large single data pull, followed by
> summarization and/or subsetting.  Networked access kills performance, so
> you're likely not going to have all that much traffic on the dataserver.
> If you can run multiple NICs out of the box, either dedicated to a
> single analyst's PC, or on a load-balanced network, you'll improve
> throughput markedly.  Contention on the fileserver itself is likely to
> be low, but SCSI will help you there.
> 
     Dual attached network.  Got it.

> The pessimal configuration is when your SAS programmers try to do *all*
> their work on the fileserver, and there's always some yahoo who does.
> Saving working sets back is reasonable, but using the server for
> SASWORK, SASSSORT, or other temporary or scratch space, really loads up
> network traffic.  Discourage this if possible.

     We will have a large SASWORK on the application server.  A
     SAS/Compaq rep is going to come out and train our SAS folks on how
     to get the processing going on in the right place.  
> 
> Peace.
     and Plenty
> 

> -- 
> Karsten M. Self <kmself@ix.netcom.com>        http://kmself.home.netcom.com/
>  What Part of "Gestalt" don't you understand?
     I am having trouble with the "alt"

     Thanks for your help,
          ~Michael