Subject: CCL:Mass storage devices

From: Eugene Leitl <[email-masked]>
Date: Wed, 8 Mar 2000 15:09:20 -0800 (PST)

Jochen K?pper writes:

 > Use RAID. That defers the first problem back to OS' or hardware
 > designers. Striping should give you best average performance.

I would add to this very good advice the following:

1) use modern, large EIDE drives (currently, 40 GBytes for ~$250:
   http://www.pricewatch.com/1/26/2119-1.htm ). If money is not an
   issue at all, use 10 k rpm (UW..etc)SCSI drives:
   http://www.pricewatch.com/1/26/2150-1.htm
   If you have a money printing press, use hardware RAID with them:
   http://www.pricewatch.com/1/26/1537-1.htm
   http://www.linuxdoc.org/HOWTO/mini/DPT-Hardware-RAID.html

2) Use several of large, modern EIDE drives as soft or hard RAID.
   http://www.linuxdoc.org/HOWTO/Software-RAID-HOWTO.html
   if you use EIDE drives, put them on individual EIDE host adapter 
   interface. These are ~$30 apiece, for instance:
   http://www.buy.com/comp/product.asp?sku=10023443

3) if you're using Linux, use lots of RAM. 512 MByte-1 GByte or more
   (make sure it is being recognized, you might have to supply 
   options at boot, though probably not with newer kernels). Linux 
   utilizes extra memory for file caching, which can speed up things 
   dramatically.
 
4) use a recent (preferably, cutting, not bleeding edge) kernel, 
   because sometimes improvements in caching algorithms/drivers 
   translate in very noticeable improvement in overall performance. 

5) if you have large files (>2 GByte) you'll need 64 bit clean file
   systems (patches for Linux vanilla ext2 are available). Also, look
   around on http://www.beowulf-underground.org/ , there are 
   patches/software to be found there which also might improve 
   performance even for nonparallel systems.

Regards,

Eugene Leitl

 > Many OS's allow software RAID without any additional hardware, but
 > then if you are willing to spend the cash, you could use hardware RAID
 > as well :-)
 > Fail-safety is something else to be considered, but probably not for
 > your "scratch"-files.