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Full Discussion: Software RAID
Special Forums Hardware Filesystems, Disks and Memory Software RAID Post 302378342 by pludi on Monday 7th of December 2009 03:50:17 PM
Old 12-07-2009
Quote:
Originally Posted by mojoman
Code:
[root@drill proc]# mdadm --detail /dev/ha0
mdadm: cannot open /dev/ha0: No such file or directory
[root@drill proc]# mdadm --detail /dev/md0
/dev/md0:
        Version : 00.90.03
  Creation Time : Thu Mar 26 19:20:00 2009
     Raid Level : raid1
     Array Size : 483336128 (460.95 GiB 494.94 GB)
  Used Dev Size : 483336128 (460.95 GiB 494.94 GB)
   Raid Devices : 2
  Total Devices : 2
Preferred Minor : 0
    Persistence : Superblock is persistent

    Update Time : Sun Dec  6 04:07:03 2009
          State : clean
 Active Devices : 2
Working Devices : 2
 Failed Devices : 0
  Spare Devices : 0

           UUID : 4a9f08c9:339514a7:b9ef28ff:12bbcfdb
         Events : 0.6

    Number   Major   Minor   RaidDevice State
       0     253        2        0      active sync   /dev/VolGroup_a/Logical_a
       1     253        3        1      active sync   /dev/VolGroup_b/Logical_b

In your case, /dev/md0 is the software RAID device. It's a RAID1 without any errors, using 2 devices, neither of them degraded or with errors. But none of the 2 is a physical device, but they are logical devices inside LVM volume groups. Which physical devices belong to it you'll see by checking the output of vgdisplay.

From my point of view, it's been set up exactly the wrong way around. If a device fails, you'll have to rescue the volume group and logical devices before you'll be able to rescue the RAID. Also, any data not in the RAID will probably be lost, or at least will have to be restored from backup.

Usually, you create a RAID (in hard- or software), on top of which you create logical devices. That way, if a drive fails it's easy to replace, and the LVM won't even notice a part of it went missing for a while.
 

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ASR(4)							   BSD Kernel Interfaces Manual 						    ASR(4)

NAME
asr -- driver for Adaptec I2O based SCSI/ATA host bus adapters SYNOPSIS
device asr DESCRIPTION
The Adaptec asr driver provides access to disks and disk arrays controlled by I2O based host bus adapters and SmartRAID SCSI RAID adapters through the standard SCSI disk da(4) interface. The supported adapters provide 64 bit PCI, Compact PCI, Zero Channel PCI, and up to four channels of Ultra2, Ultra 160, or Ultra320 SCSI, or two channels of 1GB Fibre. All support RAID-0, RAID-1, RAID-10, RAID-5 and RAID-50 arrays. All SCSI target types are supported. For the ATA based controllers, one IDE drive per channel is supported. Hot-swapping of IDE drives is not supported at this time. All host bus adapters must be configured before they can be used with any operating system. Please contact Adaptec directly to obtain the latest information on configuration utilities for the adapters. Currently there are both a Motif based GUI configuration utility and a CLI based configuration utility available from the Adaptec Web site. The cards and arrays can also be configured via the BIOS based configura- tion tool (SMOR). HARDWARE
The adapters currently supported by the asr driver include the following: o Adaptec Zero-Channel SCSI RAID 2000S, 2005S, 2010S, 2015S o Adaptec SCSI RAID 2100S, 2110S o Adaptec ATA-100 RAID 2400A o Adaptec SCSI RAID 3200S, 3210S o Adaptec SCSI RAID 3400S, 3410S o Adaptec SmartRAID PM1554 o Adaptec SmartRAID PM1564 o Adaptec SmartRAID PM2554 o Adaptec SmartRAID PM2564 o Adaptec SmartRAID PM2664 o Adaptec SmartRAID PM2754 o Adaptec SmartRAID PM2865 o Adaptec SmartRAID PM3754 o Adaptec SmartRAID PM3755U2B / SmartRAID V Millennium o Adaptec SmartRAID PM3757 o DEC KZPCC-AC (LVD 1-ch, 4MB or 16MB cache), DEC KZPCC-CE (LVD 3-ch, 64MB cache), DEC KZPCC-XC (LVD 1-ch, 16MB cache), DEC KZPCC-XE (LVD 3-ch, 64MB cache) -- rebadged SmartRAID V Millennium FILES
/dev/asr* Adaptec SCSI RAID control nodes NOTES
The ATA based controllers present their devices as SCSI-like devices via CAM. For IDE drives attached to these cards, a subset of standard SCSI commands and mode pages are understood via translation performed in the card's firmware. SEE ALSO
da(4) HISTORY
The asr (Adaptec SCSI RAID) driver first appeared as the dpti2o driver under BSDi BSD/OS 3.2, then under FreeBSD 2.2.8 and was ported over to the CAM layer represented in 4.0. AUTHORS
The asr driver was kindly donated by Adaptec and is maintained by Mark Salyzyn <mark_salyzyn@adaptec.com>. This manual page was written by Mark Salyzyn and fixed up by Jeroen Ruigrok van der Werven <asmodai@FreeBSD.org>. BSD
July 14, 2004 BSD
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