Re: NEWBIE Q: expanding hardware RAID

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

 



Hi David,
 Thank you very much for you detailed and patient response.

 My RAID controller is PERC 5/E and the external Dell drives are setup
up in RAID5. (I installed Dell's OpenManage Server Administration
which gave me the details of my existing RAID). Here's some output
(that might be useful):

$ cat /proc/scsi/scsi
Attached devices:
Host: scsi0 Channel: 00 Id: 00 Lun: 00
  Vendor: DELL     Model: MD1000           Rev: A.00
  Type:   Enclosure                        ANSI SCSI revision: 05
Host: scsi0 Channel: 02 Id: 00 Lun: 00
  Vendor: DELL     Model: PERC 5/E Adapter Rev: 1.00
  Type:   Direct-Access                    ANSI SCSI revision: 05
Host: scsi1 Channel: 00 Id: 06 Lun: 00
  Vendor: PE/PV    Model: 1x2 SCSI BP      Rev: 1.0
  Type:   Processor                        ANSI SCSI revision: 02
Host: scsi1 Channel: 01 Id: 00 Lun: 00
  Vendor: MegaRAID Model: LD 0 RAID1   34G Rev: 521X
  Type:   Direct-Access                    ANSI SCSI revision: 02

I also updated the controller's ancient firmware and drivers (though
these will take effect only after a reboot).

 Once all users on my system have backed-up their data, I will be able
to do a reboot and any further maintenance (which hopefully should be
soon). (This was my only reason for not being able to do a reboot
yet.)

 However, after reading through all the documentation on the Server
Administration software and the controller manuals, I'm still unsure
if expanding a hardware RAID is possible (and if so, how to perhaps do
it). (Some parts of the manuals seem to indicate that simply
installing the additional HDs is enough; the raid controller (during
reboot) will automatically detect the new drives and expand the RAID -
not sure if I've interpreted this correctly or not).

Any tips at all would be very helpful!

Thanks
Best
Anil

On Tue, Sep 1, 2009 at 12:33 AM, David Lethe<david@xxxxxxxxxxxx> wrote:
> The answer to #2 is a function of the make/model of hardware RAID, and the
> configuration.   Sorry.  While there are standards for what RAID-5 means,
> there is no built-in universal program that will configure all RAID
> subsystems.
>
> Dell supports several RAID controllers.
>
> The answer to #1 is also, unfortunately a function of the make/model of
> RAID.  You can enter cat /proc/scsi/scsi and see if PERC, or DELL or LSI
> shows up in the vendor field.  If so, highly probable it is RAID, but that
> won't tell you if it is RAID0, 1, 10, 5, etc...   If there are entries in
> /dev/mpt, then it is a LSI-based RAID controller. (But not necessarily in a
> hardware protected RAID mode)
>
> If it says PERC or LSI, it is definitely a RAID config, but the config could
> be set up so you see individual disk drives, or it could be a n-DISK RAID5
> that is partitioned into individual disks.
>
> If it is hardware RAID, then I suggest, based solely on the newbie questions
> that you find the documentation and read a bit, and run whatever software
> that comes with it to assess the situation.    Expanding a hardware RAIDset,
> can be dangerous, especially if you are unfamiliar with it.
>
> For example, maybe the firmware is ancient, or you have a lot of bad blocks
> because you never fixed them, or even knew about running consistency/repairs
> . If you don't know what you are doing, then you can easily lose everything.
>
> So FIRST thing I would do before so much as powering off is a full backup.
> If you don't know what you have, then obviously you can't properly maintain
> it.  (Not trying to put you down, but if you aren't willing or able to
> examine the configuration while it is powered on, and you don't want to do a
> reboot indicates the system may be unstable, or is mission critical and has
> no maintenance window, or you just don't know how to bring it back up
> properly.  If any of those are the case, back up before something fails.
>
> Remember disk drives have a 100% probability of failure ... Eventually.  You
> just don't want it to happen while you are responsible for the system.
>
>
> P.S. Did you just try the simple thing of logging onto Dell's support site
> and entering the service tag and get the configuration that they originally
> shipped?
>
>
>
> On 8/31/09 7:53 PM, "Anil Raj" <anil.calvin@xxxxxxxxx> wrote:
>
>> current RAID setup to include
>> the new drives. Is there any documentation on expanding hardware RAID?
>> ( I found doc on growing software RAID on the mailing list's wiki but
>> none on hardware RAID.)
>>
>> I really really hope someone can help me with these questions, please.
>> Also, if this is not the right forum (and there is a more relevant
>> forum) for these questions, please do let
>
>
--
To unsubscribe from this list: send the line "unsubscribe linux-raid" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html

[Index of Archives]     [Linux RAID Wiki]     [ATA RAID]     [Linux SCSI Target Infrastructure]     [Linux Block]     [Linux IDE]     [Linux SCSI]     [Linux Hams]     [Device Mapper]     [Device Mapper Cryptographics]     [Kernel]     [Linux Admin]     [Linux Net]     [GFS]     [RPM]     [git]     [Yosemite Forum]


  Powered by Linux