Redundant NFS storage setup (part 3) : The disappointingPERC5/E(solved?)

Fri Jan 4 08:48:25 CST 2008

Now if there was only a way to specify those options in kickstart and I'd be set!  Thanks for the links, they are very useful.

--
Thanks,
Kevin Landreth, RHCE
Technology Architect 

-----Original Message-----
From: Harald_Jensas at Dell.com [mailto:Harald_Jensas at Dell.com] 
Sent: Friday, January 04, 2008 1:37 AM
To: pmdyer at ctgcentral2.com
Cc: Landreth, Kevin; linux-poweredge at lists.us.dell.com
Subject: RE: Redundant NFS storage setup (part 3) : The disappointingPERC5/E(solved?)

Hi,

Please note that sector numbers start with One not Zero.

Have a look at Footnote Nbr 5 in this WikiPedia article if you don't belive me. :)

http://en.wikipedia.org/wiki/Master_boot_record#endnote_5

--
Harald

> -----Original Message-----
> From: Paul M. Dyer [mailto:pmdyer at ctgcentral2.com]
> Sent: 04 January 2008 01:07
> To: Jensas, Harald
> Cc: klandreth at theplanet.com; linux-poweredge-Lists
> Subject: Re: Redundant NFS storage setup (part 3) : The
> disappointingPERC5/E(solved?)
> 
> great article.  But just one followup question:
> 
> Shouldn't the starting sector be 127, since sector 0 is the first, and
> default sector 63 is the 64th??
> 
> Paul
> 
> ----- Original Message -----
> From: "Harald Jensas" <Harald_Jensas at dell.com>
> To: klandreth at theplanet.com, linux-poweredge at lists.us.dell.com
> Sent: Thursday, January 3, 2008 1:04:14 PM (GMT-0600) America/Chicago
> Subject: RE: Redundant NFS storage setup (part 3) : The
> disappointingPERC5/E(solved?)
> 
> Kevin, Did you ever try to create your Hardware RAID striped partitions
> aligned?
> This will cause less stripe crossings and thus less parity to calculate
> for RAID 5 writes. It should also improve read performance.
> 
> In this article they report up to 30% performance increase, in their
> tests, with properly aligned partitions.
> http://insights.oetiker.ch/linux/raidoptimization.html
> 
> Assuming block size is 512 bytes.
> If Stripe Size is (64KB/512 byte = 128 Blocks) align the partition to
> block 128.
> If Stripe Size is (128KB/512 byte = 256 Blocks) align the partition to
> block 256.
> 
> 1. Enter fdisk /dev/sd<x> where <x> is the device suffix.
> 2. Determine if any partitions already exist.
> 3. Type n to create a new partition.
> 4. Type p to create a primary partition.
> 5. Type 1 to create partition No. 1.
> 6. Select the defaults to use the complete disk.
> 7. Type t to set the partition's system ID.
> 8. Type in the code for the partition type you want.
> 9. Type x to go into expert mode.
> 10. Type b to adjust the starting block number.
> 11. Type 1 to choose partition 1.
> 12. Type 128 to set it to 128 (the array's stripe element size).
> 13. Type w to write label and partition information to disk.
> 
> 
> 
> --
> Harald Jensås
> 
> > -----Original Message-----
> > From: linux-poweredge-bounces at dell.com [mailto:linux-poweredge-
> > bounces at dell.com] On Behalf Of Landreth, Kevin
> > Sent: 03 January 2008 17:40
> > To: linux-poweredge-Lists
> > Subject: RE: Redundant NFS storage setup (part 3) : The
> > disappointingPERC5/E(solved?)
> >
> > Using setra won't help with writes IIRC.  Has write performance seen
> > any
> > difference?  In the applications where I use a Perc5 card, writes are
> > my
> > biggest performance problem and I'd like to see if you write
> > performance
> > is still suffering.  Using setra will help with software raid just
> the
> > same too I believe so I wouldn't write your problem off as "solved"
> > just
> > yet.
> >
> > Also, could you try ext3 with -E stride=32 (for 128K) and stride=16
> > (for
> > 64K) and see if you still have the performance issues you had before.
> > I
> > know this may not be ideal for your application but testing with two
> > file systems provides better conclusive answers for everyone beyond a
> > reasonable doubt.
> >
> > Thanks for all the testing, this is really useful data you are
> > providing
> > everyone.
> >
> > --
> > Thanks,
> > Kevin Landreth, RHCE
> > Technology Architect
> >
> >
> > -----Original Message-----
> > From: linux-poweredge-bounces at dell.com
> > [mailto:linux-poweredge-bounces at dell.com] On Behalf Of Matthias Saou
> > Sent: Thursday, January 03, 2008 9:46 AM
> > To: linux-poweredge at dell.com
> > Subject: Re: Redundant NFS storage setup (part 3) : The
> > disappointingPERC5/E (solved?)
> >
> > Hi all,
> >
> > Looking for information on XFS filesystem options, I found this very
> > instructive thread :
> >
> > http://oss.sgi.com/archives/xfs/2007-09/msg00322.html
> >
> > I read about this simple change in one of the posts, which improved
> > performance a lot for the person making the benchmark, so I ran it :
> > # blockdev --setra 16384 /dev/sdb
> >
> > I now get 500-520MB/s read speed with hardware RAID5 where I used to
> > get 30-35MB/s... pretty amazing, I must admit.
> >
> > Looking at the man page, this just sets a read-ahead value... I'm
> > puzzled yet very happy!
> >
> > Would any of the others who reported slow read speeds with their
> PERC5s
> > and MD1000s care to also try it and report back to the list?
> >
> > I'll continue digging, but in the meantime, it seems like my
> "problem"
> > might be solved.
> >
> > Matthias
> >
> > --
> > Clean custom Red Hat Linux rpm packages : http://freshrpms.net/
> > Fedora release 8 (Werewolf) - Linux kernel 2.6.23.9-85.fc8
> > Load : 0.50 0.65 1.03
> >
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