From: AndyLiebman@aol.com
Message-ID: <125.26e5f7ec.2cd178ac@aol.com>
Date: Wed, 29 Oct 2003 15:10:20 EST
Subject: Why can't I put Log File on its own drive/partition? 
To: linux-xfs@oss.sgi.com
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According to information on the XFS home page, writing XFS files can be sped 
up by as much as 30 percent by having the "metadata" or "journal" file stored 
on a separate drive. 

I am trying do use that "speed up" proceedure without any success. 

Here's my setup. I have 6 Firewire Drives arranged into three RAID 1 arrays 
(md0, md1, md2). Then the  3 RAID 1 arrays are combined into one RAID 0 array 
(md3). The end result is a single RAID 10 array. 

I don't have any trouble putting XFS on the array with a simple 
mkfs.xfs -f -b size=4096 /dev/md3 -- and then mounting the array with  
mount -t xfs /dev/md3 /home/raid1

However, I have been unable to configure XFS on the array so that the journal 
goes on a separate drive. I am wondering if I'm doing something wrong. 

The place where I'm trying to put the journal file is a 4 GB partition on an 
internal IDE drive. 
The command  mkfs.xfs -f -l logdev=/dev/hdb3,size=10000b -b size=4096 
/dev/md3  is accepted by the system. It looks as if I formatted the RAID with XFS and 
put the journal on in a separate place. 

But when I try to mount the RAID as I did above, I get the following error: 
mount:  wrong fs type, bad option, bad superblock on /dev/md3 
            or too many mounted file systems. 

I believe I also tried something like   mount -t xfs logdev=dev/hdb3   
/dev/md3.   
I think I also tried   mount -t xfs logdev=dev/hdb3,size=10000b   /dev/md3

Does anybody have any ideas about what the trouble is? Am I issuing the wrong 
commands? Is it impossible to put the journal on the IDE partition?  It's a 
primary partition at the end of a drive. I've tried marking the partition with 
fdisk as type 83/Linux. Also tried (Raid Auto Detect). Same problem either 
way. 

I vaguely remember something about the place where I put the journal having 
to be exactly the same number of blocks as the size that's specified in the 
"logdev=dev/location,size=xxxxxb"  line. If that's true, I have no idea how to 
accomplish that.

Thanks in advance for the help. I'm about to launch into storing a lot of 
data on the RAID and I would like to set it up so that it works as efficiently as 
possible. 

Regards, 
Andy Liebman