Sponsored Content
Full Discussion: Reconstructing RAID
Special Forums Hardware Filesystems, Disks and Memory Reconstructing RAID Post 302695721 by tonyaldr on Monday 3rd of September 2012 02:37:34 PM
Old 09-03-2012
Reconstructing RAID

I am trying to reconstruct a failed 4 disk RAID5 Western Digital ShareSpace device using 3 of the 4 disks connected via USB to an Ubuntu 12.04 machine. I get what seems like a successful re-assemble from -

Code:
mdadm --assemble --force /dev/md2 /dev/sde4 /dev/sdf4 /dev/sdg4
mdadm: /dev/md2 has been started with 3 drives (out of 4).
But then when I try to mount, it fails.  I am logged in as root and when I try to troubleshoot with mdadm, I get odd returns such as -
mdadm --examine /dev/md2
mdadm: No md superblock detected on /dev/md2.
Also, the system can't seem to find the volume -
vgscan -v
    Wiping cache of LVM-capable devices
    Wiping internal VG cache
  Reading all physical volumes.  This may take a while...
    Finding all volume groups
  No volume groups found

I read in some other posts that the WD system uses LVM2.  Could that be the issue?  Here is the output from mdadm --detail
mdadm --detail /dev/md2
/dev/md2:
        Version : 0.90
  Creation Time : Mon Oct 19 10:26:15 2009
     Raid Level : raid5
     Array Size : 5854981248 (5583.75 GiB 5995.50 GB)
  Used Dev Size : 1951660416 (1861.25 GiB 1998.50 GB)
   Raid Devices : 4
  Total Devices : 3
Preferred Minor : 2
    Persistence : Superblock is persistent

    Update Time : Sun Sep  2 15:22:50 2012
          State : clean, degraded 
 Active Devices : 3
Working Devices : 3
 Failed Devices : 0
  Spare Devices : 0

         Layout : left-symmetric
     Chunk Size : 64K

           UUID : 4c4952ae:1477d756:234bdad8:bdaa1368
         Events : 0.9246753

    Number   Major   Minor   RaidDevice State
       0       8       84        0      active sync   /dev/sdf4
       1       8       68        1      active sync   /dev/sde4
       2       0        0        2      removed
       3       8      100        3      active sync   /dev/sdg4

Here's the result of the mount attempt-
mount -t auto dev/md2 /mnt/raid
mount: special device dev/md2 does not exist

Appreciate any assistance! Thanx!

Last edited by Neo; 11-21-2017 at 09:59 AM..
 

9 More Discussions You Might Find Interesting

1. UNIX for Dummies Questions & Answers

reconstructing a record in a diffrent order

Can sed be used to take a existing record and reverse the order of defined character placement if there is no delimeters? existing record: 0123456789CO expected result: 9876543210CO if there were delimeters I could define the delimeter and each placement would have an id which I... (1 Reply)
Discussion started by: r1500
1 Replies

2. UNIX for Dummies Questions & Answers

regarding raid

Hello, I am aware that our system has two hard drives with raid but i'm not sure as to the type of raid the system uses. I tried this. # df Filesystem 512-blocks Free %Used Iused %Iused Mounted on /dev/hd4 229376 76272 67% 6748 12% / /dev/hd2 3080192... (1 Reply)
Discussion started by: h1timmboy
1 Replies

3. UNIX for Dummies Questions & Answers

RAID software vs hardware RAID

Hi Can someone tell me what are the differences between software and hardware raid ? thx for help. (2 Replies)
Discussion started by: presul
2 Replies

4. Solaris

implementing RAID 1 from RAID 5

Dear ALl, I have a RAID 5 volume which is as below d120 r 60GB c1t2d0s5 c1t3d0s5 c1t4d0s5 c1t5d0s5 d7 r 99GB c1t2d0s0 c1t3d0s0 c1t4d0s0 c1t5d0s0 d110 r 99GB c1t2d0s4 c1t3d0s4 c1t4d0s4 c1t5d0s4 d8 r 99GB c1t2d0s1 c1t3d0s1... (2 Replies)
Discussion started by: jegaraman
2 Replies

5. Solaris

Creation of Raid 01 and Raid 10

Hello All, I have read enough of texts on Raid 01 and Raid 10 on solaris :wall: . But no-where found a way to create them using SVM. Some one pls tell me how to do or Post some link if that helps. TIA Curious solarister (1 Reply)
Discussion started by: Solarister
1 Replies

6. AIX

SCSI PCI - X RAID Controller card RAID 5 AIX Disks disappeared

Hello, I have a scsi pci x raid controller card on which I had created a disk array of 3 disks when I type lspv ; I used to see 3 physical disks ( two local disks and one raid 5 disk ) suddenly the raid 5 disk array disappeared ; so the hardware engineer thought the problem was with SCSI... (0 Replies)
Discussion started by: filosophizer
0 Replies

7. UNIX for Dummies Questions & Answers

Need help with RAID.

Hi Gurus, Can any one explain me the difference between hardware RAID and s/w RAID. Thanks in Advance. (1 Reply)
Discussion started by: rama krishna
1 Replies

8. Solaris

Software RAID on top of Hardware RAID

Server Model: T5120 with 146G x4 disks. OS: Solaris 10 - installed on c1t0d0. Plan to use software raid (veritas volume mgr) on c1t2d0 disk. After format and label the disk, still not able to detect using vxdiskadm. Question: Should I remove the hardware raid on c1t2d0 first? My... (4 Replies)
Discussion started by: KhawHL
4 Replies

9. Red Hat

RAID Configuration for IBM Serveraid-7k SCSI RAID Controller

Hello, I want to delete a RAID configuration an old server has. Since i haven't the chance to work with the specific raid controller in the past can you please help me how to perform the configuraiton? I downloaded IBM ServeRAID Support CD but i wasn't able to configure the video card so i... (0 Replies)
Discussion started by: @dagio
0 Replies
SCSI(4) 						     Kernel Interfaces Manual							   SCSI(4)

Name
       SCSI - Small Computer System Interconnect

Description
       The  ULTRIX  system interfaces to disk and tape devices through the Small Computer System Interconnect (SCSI).  Initial ULTRIX SCSI support
       is limited to the Digital-supplied mass storage devices.  The following devices are fully supported on the ULTRIX system:

       o    Winchester disks: RZ22, RZ23, RZ23L, RZ24, RZ55, RZ56, RZ57, RX23, RX26, RX33

       o    Magnetic tapes: TZ30, TZK50, TLZ04, TSZ05, TKZ08, TZK10

       o    Optical disks: RRD40, RRD42

       Under the ULTRIX operating system, a SCSI device is referred to by its logical name.  Logical names take the following form:
       nn#
       The nn argument is the two-character name; the number sign (#) represents the unit number.  The two character names for SCSI devices are:

       rz  -  RZ22, RZ23, RZ23L, RZ24, RZ55, RZ56, RZ57, RX23, RX26, RX33, RRD40, RRD42 disks

       tz  -  TZ30, TZK50, TLZ04, TSZ05, TKZ08, and TZK10 tapes

       The unit number is a combination of the SCSI bus number, either 0, 1, ... and the device's target ID number.   The  unit  number  is  eight
       times  the  bus	number plus the target ID.  For example, an RZ23 disk at target ID 3 on bus 0 would be referred to as rz3; a TZK50 tape at
       target ID 5 on the second SCSI bus would be referred to as 13.

       The SCSI bus has eight possible target device IDs.  By default, one is allocated to the system.	This allows for a maximum of seven  target
       devices connected to a SCSI bus.

Restrictions
       The ULTRIX SCSI device driver does not operate with optical disks, other than the Digital-supplied devices.

       The SCSI driver attempts to support on a best effort basis, non-Digital-supplied winchester disks and magnetic tapes.

       The following notes apply to the driver's handling of non-Digital-supplied disks:

	  o   These disks are assigned a device type of RZxx, instead of RZ22, RZ23, RZ23L, RZ55, RZ56, RZ57, RX23, RX26, or RX33.  The RZxx disks
	      follow the same logical device naming scheme as the Digital-supplied disks.

	  o   During the autoconfigure phase of the system startup, the driver prints the contents of the SCSI vendor  ID,  product  ID,  and  the
	      revision level fields of the inquiry data return by the SCSI device.

	  o   RZxx  disks  are	assigned a default partition table. The default table can be modified by editing the sz_rzxx_sizes[8] entry in the
	      file The utility can also be used to modify the partition table on a RZxx disk.

	  o   The only logical unit number (LUN) supported for each target ID is 0.

See Also
       rz(4), tz(4), chpt(8)

																	   SCSI(4)
All times are GMT -4. The time now is 10:07 PM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy