epike on Thu, 27 Feb 2003 13:01:08 -0500


[Date Prev] [Date Next] [Thread Prev] [Thread Next] [Date Index] [Thread Index]

Re: [PLUG] organizing files on software Raid (SCSI)


hi

Heres just one more option for you,  if you
want to do away with the IDE disk and want
to use just the 2 scsi disks you got.  I've set
this up for a friend of mine ( 2 SCSI disks
hanging on a internal scsi card).  The
system boots on /dev/sda:


-------------
Filesystem            Size  Used Avail Use% Mounted on
/dev/sda5            1008M  153M  804M  16% /
/dev/sda1             124M   18M   99M  16% /boot
/dev/sdb2            1008M  211M  746M  22% /cache
none                  503M     0  503M   0% /dev/shm
/dev/sdb1             2.0G   34M  1.8G   2% /tmp
/dev/sda2             4.9G  3.2G  1.5G  68% /usr
/dev/sdb5             985M  410M  525M  44% /misc
/dev/md0               25G  636M   23G   3% /var
/dev/md1              985M   23M  912M   3% /log
/dev/cdrom            675M  676M     0 100% /mnt/cdrom
-------------
[root@xxxxxxxxxx root]# swapon -s
Filename                        Type            Size    Used    Priority
/dev/sda3                       partition       1048568 37320   -1
/dev/sdb3                       partition       1048568 0       -2
[root@xxxxxxxxxx root]# 
-------------
[root@xxxxxxxxxx root]# cat /proc/mdstat
Personalities : [raid1] 
read_ahead 1024 sectors
md1 : active raid1 sdb7[1] sda7[0]
      1024896 blocks [2/2] [UU]
      
md0 : active raid1 sdb6[1] sda6[0]
      26624896 blocks [2/2] [UU]
      
unused devices: <none>
[root@xxxxxxxxxx root]#
-------------

As you see sda and sdb have both raid (level 1) and 
non-raid partitions.  The system boots on
/dev/sda.  the partitions /, /boot,
/tmp, /usr , and swap spaces are scattered on 
non-raid paritions, but /var and /log (which
where our really important data resides) are
on raid.  (Your filesystem requirement will 
be different of course.)  

In this scenario
I understand that if /dev/sda disk is to die,
i'll have to reinstall the OS on another disk
and somehow mount /dev/sdb (thats acceptable
to me since i do no kernel recompiles for 
this machine and I only care about /var and /log)
If /dev/sdb dies it wont boot and we'll have 
to get a disk quick, partition and format it,
and raidhotadd and mount it.

With 2 disks this is the best i've come up with
at the time.  But if i were to do it again I
would have tried to setup root raid (all partitions
on raid).  But At that time i was afraid of facing
kernel support problems later if i have to recover
the disks.


e.pike
_________________________________________________________________________
Philadelphia Linux Users Group        --       http://www.phillylinux.org
Announcements - http://lists.netisland.net/mailman/listinfo/plug-announce
General Discussion  --   http://lists.netisland.net/mailman/listinfo/plug