Author: Robert Sander <ml-linux-xfs@xxxxxxxxxxxxxxx>
Date: Fri, 11 Apr 2003 06:24:11 +0000 (UTC)
When creating an XFS volume on an external hardware RAID which has a stripe size of 128 1024k blocks, what are the preffered values for sunit and swidth. Or is there no performance degrade when usin
With all due respect to the XFS guys, the manpage section on sunit and swidth is very confusing. Would someone be willing to write up a more understandable explanation and post it to the FAQ since su
hi Derek - Which parts do you find confusing? Not that I disagree. :) For my part, I think the different ways of specifying the values (i.e. different options for different units) is a bit confusing.
Basically: It's never been entirely clear to me exactly the difference between a "stripe unit" and a "stripe width" nor the relation between "stripe unit" and "stripe width" and the size of the stri
I'll quote below the response I got from Steve Lord way back when I asked this. The first level of quoting is me: \begin{quote} Actually this is incorrect, you need -d sunit=64,swidth=448 The sunit i
Author: Christian Guggenberger <Christian.Guggenberger@xxxxxxxxxxxxxxxxxxxxxxxx>
Date: Fri, 11 Apr 2003 18:26:01 +0200
no, su=64k _or_ sunit=128 ! having an 8 disk RAID5, you'll need swidth=(8-1)*sunit (=896 for your example) - if I remember some posts about that topic correctly.( a 8 disk RAID5 has 7 "data" disks in
(in the meanwhile, I've gone and made a Linux software-RAID5 box in the lab to play with) It gets even more confusing when I do: on software RAID5 with 4 disks and 64k stripes, and the status screen
All the output units are in fsblocks, on the mkfs command line it does not know what you blocksize is all the time. Steve -- Steve Lord voice: +1-651-683-3511 Principal Engineer, Filesystem Software
Author: Robert Sander <ml-linux-xfs@xxxxxxxxxxxxxxx>
Date: Fri, 11 Apr 2003 17:36:52 +0000 (UTC)
So swidth is dependent of the total number of disks in the RAID? What if there are two or more partitions on the SCSI device the hardware RAID controller shows to the OS? What are the options for swi
Author: Robert Sander <ml-linux-xfs@xxxxxxxxxxxxxxx>
Date: Fri, 11 Apr 2003 21:54:40 +0000 (UTC)
That may be the case with software RAID, where mkfs.xfs is able to get the stripe size from the md driver. But with at least our hardware RAID boxen sunit and swidth are both set to 0 (zero). My only
In general, no. But it depends on the internal workings of your hardware RAID controller. Only way to find out is to experiment with different values and your anticipated I/O load. -- Martin K. Pete