Nah, RAID 10's performance will always be twice as fast as RAID 50.
Look at the writes required:

WRITE to RAID 10:
  Write data to primary stripe
  Copy to backup stripe

WRITE to RAID 50:
  Write data to primary stripe
  Update the parity on primary stripe
  Copy data to secondary stripe
  Update the parity on secondary stripe

READ from RAID 10:
  Read data from primary stripe (half of the drives)

READ from RAID 50:
  Read data from primary and secondary stripes (all of the drives)


The advantage of RAID 50 over RAID 10 is better economy of drive space.
Consider six drives, all 100 gigabytes:

RAID 10:
  Three drives for storage
  Three drives for backup
  Total usuable space = 300 gigs

RAID 50:
  Two drives on each stripe used for storage
  One drive on each stripe used for parity
  Total usable space = 400 gigs

If you applied RAID 50 to my stack here, with 24 total drives, you would
get TONS more space, but performance would drop by 50%, which would
suck, because my system is right on the 60% mark for the throughput of
the stack.

Keith


> I guess from my perspective I'm down to a choice of one 
> thing, RAID 10 or RAID 50.  I figure that I will build an 8 
> drive system, and I could either go with a 4 drive RAID 10 
> configuration with 2 each, or striped RAID 5 array.  It seems 
> that I would need 3 striped drives in RAID 10 (6
> total) to get the performance of a RAID 50 implementation, 
> however that's only for one drive of course.  The advantage 
> goes down as you dedicate functions to separate sets of 
> drives in RAID 10.  There's no equation that can tell you off 
> the cuff what's best because it depends on the application 
> and how many sequential reads and writes you are doing at one 
> time and if those can be split up somewhat evenly across 
> different drive letters.
[AUTOMATED NOTE: Your mail server [63.147.33.8] is missing a reverse DNS entry. All 
Internet hosts are required to have a reverse DNS entry. The missing reverse DNS entry 
will cause your mail to be treated as spam on some servers, such as AOL.]

---
[This E-mail was scanned for viruses by Declude Virus (http://www.declude.com)]

---
This E-mail came from the Declude.JunkMail mailing list.  To
unsubscribe, just send an E-mail to [EMAIL PROTECTED], and
type "unsubscribe Declude.JunkMail".  The archives can be found
at http://www.mail-archive.com.

Reply via email to