SATA 1 vs SATA 3 won't change the seek performance of the drive,
unless your stay fully within the drives cache.
Only 2 things affect how many iops you can get from a drive. The
physical diameter and the speed. You can affect the physical diameter
of the drive by selecting how much of the drive you use, like only
using 200gigs out of a 500gig drive.
If you do opt for raid6, that would be a huge cpu overhead, and if you
stick with 4 drives, not worth it, every write would hit atleast 3
drives then, instead of just two they do currently, with no gain of
space.
Quoting "Daniel L. Miller" <dmil...@amfes.com>:
A little OT - but I've seen a few opinions voiced here by various
admins and I'd like to benefit.
Currently running a single combined server for multiple operations -
fileserver, mailserver, webserver, virtual server, and whatever else
pops up. Current incarnation of the machine, after the last
rebuild, is an AMD Opteron 4180 with a Supermicro MB using ATI SB700
chipset - which means it supports SATA 3.0.
Current storage is one o/s drive, and a 4-drive RAID10 array. The
RAID10 is using the Linux softraid via mdadm. The drives are
Seagates - ST3160811AS. So it's 320GB of storage, and SATA 1.5.
I'm seeing some warnings & errors in my logs & dmesg - and Google
tells me this can the result of several factors, including the hard
drives. I haven't seen any SMART warnings as yet - but I am getting
a little nervous and thinking about upgrading the storage.
At this time, I'm just interested in recommendations for hard drives
& partitioning strategy. At the time I created the RAID10 array - I
was still in the early stages of learning these technologies (not
that I know that much more now!) so I probably didn't take advantage
of any of the advanced settings such as stripe size, cluster size,
etc. I am using XFS.
As part of the potential upgrade, I'm considering changing to RAID6
- seems a bit more efficient use of space. I see no reason for SSD
- I think a set of reasonable 7200rpm drives should be just fine.
What I don't know is, compared to my current 4 drive RAID10 with
SATA 1.5, would even a single SATA 3 drive be comparable in terms of
seek performance? Should I stick with the RAID-10?
--
Daniel
