building a RAID system

Alvin Oga alvin at Mail.Linux-Consulting.com
Wed Oct 8 17:46:31 EDT 2003


hi ya daniel

>  On Wed, 8 Oct 2003, Daniel Fernandez wrote:
> 
> > Hi,
> > 
> > I would like to know some advice about what kind of technology apply
> > into a RAID file server ( through NFS ) . We started choosing hardware
> > RAID to reduce cpu usage.
> > 
> > We have two options , SCSI RAID and ATA RAID. The first would give the
> > best results but on the other hand becomes really expensive so we have
> > in mind two ATA RAID controllers:
> > 
> >                 Adaptec 2400A
> > 		3Ware 6000/7000 series controllers
> > 
> > Any one of these has its strong and weak points, after seeing various
> > benchmarks/comparisons/reviews these are the only candidates that
> > deserve our attention.

good points about ata raid
	- large disks storage ( 300GB drives at $300 each +/- )
	- get those drives w/ 8MB buffer disk cache
	- cheap ... can do with software raid or $40 ata-133 ide 
	controller

	- $300 more for making ata drives appear like scsi drives
	with 3ware raid controllers 

	- slower rpm disks ... usually it tops out at 7200rpm

	- it supposedly can sustain 133MB/sec transfers

	- if you use software raid, you can monitor the raid status

	- if you use hardware raid, you are limited to the tools
	the hw vendor gives you tomonitor the raid status
	of pending failures or dead drives

good points about scsi ..
	- some say scsi disks are faster ... 
	- super expensive .. $200 for 36 GB .. at 15000rpm

	- it supposedly can sustain 320MB/sec transfers

if the disks does transfer at its full speed ... 320MB/sec or 133MB/sec
does the rest of the system get to keep up with processing the
data spewing off and onto the disks

independent of which raid system is built, you wil need 2 or 3
more backup systems to backup your Terabyte sized raid systems

more raid fun
	http://www.1U-Raid5.net

c ya
alvin

> > The server has a dozen of client workstations connected through a
> > switched 100Mbit LAN , all of these equipped with it's own OS and
> > harddisk, all home directories will be stored under the main server,
> > main workload (compilation and edition) would be done on the local
> > machines tough, server only takes care of file sharing.
> > 
> > Also parallel MPI executions will be done between the clients.
> > 
> > Considering that not all the workstantions would be working full time
> > and with cost in mind ¿ it's worth an ATA RAID solution ?

good p
> > 
> > 
> 
> -- 
> -------------------------------------------------------------------------- 
> Joel Jaeggli  	       Unix Consulting 	       joelja at darkwing.uoregon.edu    
> GPG Key Fingerprint:     5C6E 0104 BAF0 40B0 5BD3 C38B F000 35AB B67F 56B2
> 
> 
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