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-   -   Does this server have RAID configured correctly? (http://www.linuxquestions.org/questions/linux-server-73/does-this-server-have-raid-configured-correctly-759574/)

Nunawading 10-04-2009 06:44 AM

Does this server have RAID configured correctly?
 
Hi All,

Hopefully this is a quick question. We have a system, but we're not sure if there's RAID installed or not. It looks like it's using some form of Fake Raid. My suspicion is that the fakeraid is configured correctly, but the volume groups are actually created directly on the physical disk (sda). Is that even possible? Or is the mirror set up correctly?

I think the pertinent information is below, but I can provide as much diagnostic information as required. Let me know if there's anything else that will help?

Thanks in advance for your help.


Code:

[root@mx ~]# fdisk -l

Disk /dev/sda: 250.0 GB, 250059350016 bytes
255 heads, 63 sectors/track, 30401 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

  Device Boot      Start        End      Blocks  Id  System
/dev/sda1  *          1          13      104391  83  Linux
/dev/sda2              14      30377  243898830  8e  Linux LVM

Disk /dev/sdb: 250.0 GB, 250059350016 bytes
255 heads, 63 sectors/track, 30401 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

  Device Boot      Start        End      Blocks  Id  System
/dev/sdb1  *          1          13      104391  83  Linux
/dev/sdb2              14      30377  243898830  8e  Linux LVM

[root@mx ~]# ls /dev/mapper/
control  VolGroup00-LogVol00  VolGroup00-LogVol01

[root@mx ~]# dmraid -r
/dev/sda: ddf1, ".ddf1_disks", GROUP, ok, 488017920 sectors, data@ 0

[root@mx ~]# dmraid -b
/dev/sda:    488397168 total, "6RYAEL4Z"
/dev/sdb:    488397168 total, "6RYADTQ1"

[root@mx ~]# dmraid -s -c -c -c
ddf1_RM:488017920:128:mirror:ok:0:2:0
/dev/sda:ddf1:ddf1_RM:mirror:ok:488017920:0
/dev/sdb:ddf1:ddf1_RM:mirror:ok:488017920:0

[root@mx ~]# pvdisplay
  Found duplicate PV aLNQfrXT3tOfRa1ArmNvD7T6RK9qH0LQ: using /dev/sdb2 not /dev/sda2
  --- Physical volume ---
  PV Name              /dev/sdb2
  VG Name              VolGroup00
  PV Size              232.60 GB / not usable 6.45 MB
  Allocatable          yes (but full)
  PE Size (KByte)      32768
  Total PE              7443
  Free PE              0
  Allocated PE          7443
  PV UUID              aLNQfr-XT3t-OfRa-1Arm-NvD7-T6RK-9qH0LQ


pingu 10-05-2009 02:17 AM

You are using LVM here, not RAID.
Which you should use depends on what you want to achieve - handle diskspace efficiently or fault-tolerance?
My guess, since this is a server, is that you want fault tolerance so you should go for RAID.
Taka a look at mdadm, an application to handle software raid. You'll find a manual here: http://www.linuxmanpages.com/man8/mdadm.8.php

Nunawading 10-05-2009 02:24 AM

Thanks. Is it not possible to use LVM on top of fakeRAID?


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