Hello,
I am having a problem initializing a linear array. I am using kernel
2.2.11 patched with raid0145-19990824-2.2.11 and
raidtools-19990824-0.90.
My conf file looks like this:
raiddev /dev/md0
raid-level linear
nr-raid-disks 2
persistent-superblock 1
device /dev/sdb1
raid-disk 0
device /dev/sdc1
raid-disk 1
The system is Redhat 6.1 and I was sure to remove the raidtools rpm
that came with the system before building and installing the raidtools
I got from ftp.dk.kernel.org.
`mkraid -c /etc/raid.linear /dev/md0` with the correct force flag
gives the following output:
handling MD device /dev/md0
analyzing super-block
disk 0: /dev/sdb1, 17880313kB, raid superblock at 17880192kB
disk 1: /dev/sdc1, 17880313kB, raid superblock at 17880192kB
/dev/md0: Invalid argument
I got this same error when using the stock Redhat kernel and raidtools
packages. I also made sure nothing was running in /proc/mdstat before
attempting to initialize the linear array.
I compiled all the raid levels directly into the kernel and said 'no'
to the options Config.help said were unusable at the moment.
/proc/mdstat looks like this:
Personalities : [linear] [raid0] [raid1] [raid5]
read_ahead 1024 sectors
unused devices: <none>
Is there anything I am doing wrong or is linear just not supported
anymore because of a lack of interest?
The system is going to be a web server where the average file size is
12k and there are between 20 and 50 of these files pulled from the
raid a second.
I don't know much about raid or i/o performance but it seemed linear
may give better performance with these small file sizes and frequent
and distinct file accesses. I read ext2 distributes files across the
device in a semi-even way so two similar partitions in a linear raid
would potentially get close to the same usage.
Is there anything I am missing or that I don't properly understand?
Thanks in advance for any help!
Jacob
