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Anil Raj | 1 Sep 2009 02:53
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NEWBIE Q: expanding hardware RAID

Hi all,
 I have a dell PowerEdge 1850 server with 146gb HDs setup using (I
think) hardware RAID.

1. Is there anyway that I can confirm if the HDs are indeed setup
using hardware RAID? (hopefully without rebooting the system) And if
so, how do I determine the tech details of the RAID setup?

2. I'm planning on buying additional dell drives and was wondering how
I could go about growing/expanding the 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 me know.

Thanks much in advance!

Best,
Anil
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David Lethe | 1 Sep 2009 06:33
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Re: NEWBIE Q: expanding hardware RAID

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
(Continue reading)

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Alex Butcher | 1 Sep 2009 09:34
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Re: NEWBIE Q: expanding hardware RAID

On Mon, 31 Aug 2009, Anil Raj wrote:

> Hi all,
> I have a dell PowerEdge 1850 server with 146gb HDs setup using (I
> think) hardware RAID.
>
> 1. Is there anyway that I can confirm if the HDs are indeed setup
> using hardware RAID? (hopefully without rebooting the system) And if
> so, how do I determine the tech details of the RAID setup?
>

Assuming things haven't changed since I last used Dell's hardware RAID
controllers, you'll need 'dellmgr' from the driver kit/utils. You should
have received this on one of the CDs, or you can use the Dell tag to look up
the appropriate downloads for the machine on Dell's support site.

> 2. I'm planning on buying additional dell drives and was wondering how
> I could go about growing/expanding the 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 don't think this is possible; I think you'll need to backup, upgrade, then
restore onto the new discs. Again, using the Dell support site will find you
the manuals for the RAID controller installed in your machine.

> 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 me know.
>
(Continue reading)

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Ryan Wagoner | 1 Sep 2009 14:20
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Re: NEWBIE Q: expanding hardware RAID

I would start by installing the Dell OpenManage Server Administrator
software, which will provide you with a web gui on
https://yourserver:1311 From here you can monitor the internals of the
server, check firmware versions, and perform RAID tasks on the PERC
controller, if it has one. You should be able to download the Red Hat
version of the Open Manage software from the Dell support site. Last
time I checked the latest version was 6.1.0.

Ryan

On Mon, Aug 31, 2009 at 8:53 PM, Anil Raj<anil.calvin <at> gmail.com> wrote:
> Hi all,
>  I have a dell PowerEdge 1850 server with 146gb HDs setup using (I
> think) hardware RAID.
>
> 1. Is there anyway that I can confirm if the HDs are indeed setup
> using hardware RAID? (hopefully without rebooting the system) And if
> so, how do I determine the tech details of the RAID setup?
>
> 2. I'm planning on buying additional dell drives and was wondering how
> I could go about growing/expanding the 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 me know.
>
> Thanks much in advance!
(Continue reading)

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Anil Raj | 1 Sep 2009 23:14
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Re: NEWBIE Q: expanding hardware RAID

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.)
(Continue reading)

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Ryan Wagoner | 2 Sep 2009 04:26
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Re: NEWBIE Q: expanding hardware RAID

I've expanded a RAID 5 volume on a PERC controller in a Dell PowerEdge
2850. If your external enclosure supports hot swapping you can do this
with the system up and running. Otherwise install the new hard drive
and start up the server. Once the drive is installed open the
OpenManage Server Administrator. Expand the Storage and PERC
controller sections on the left pane and click Virtual Disks. Select
the reconfigure task from the list for the RAID 5 virtual disk. The
wizard will walk you through specifying the additional drive to be
part of the RAID 5 array. Depending on the number of drives and speeds
this process can take from a few hours to tens of hours.

I recommend doing this while the system is not being utilized after
hours. With the system idle you can speed up the rebuild rate, which
should help it complete faster. Click on the PERC controller in the
left pane and select Information/Configuration on the top bar. The
controller tasks list should give you the option to set the rebuild
rate. Just remember to set it back down when done.

After it completes you still need to expand the underlying file system
or create a new partition and file system on the additional space. If
you need assistance with this please provide the partition layout on
the RAID 5 volume and the file system being used.

Ryan

On Tue, Sep 1, 2009 at 5:14 PM, Anil Raj<anil.calvin <at> gmail.com> wrote:
> 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
(Continue reading)

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Bill Davidsen | 2 Sep 2009 18:10

Re: Write intent bitmaps.

NeilBrown wrote:
> On Tue, August 25, 2009 12:39 am, Simon Jackson wrote:
>   
>> I am trying to use write intent bitmaps on some RAID 1 volumes to reduce
>> the rebuild times in the event of hard resets that cause the md driver to
>> kick members out of my arrays.
>>
>> I used the mdadm --grow /dev/md0 --bitmap=internal  and this appeared to
>> succeed, but when I tried to examine the bitmap I get an error.
>>
>>
>> :~$ sudo mdadm --grow /dev/md0 --bitmap=internal
>> :~$ sudo mdadm -X /dev/md0
>>         Filename : /dev/md0
>>            Magic : 00000000
>> mdadm: invalid bitmap magic 0x0, the bitmap file appears to be corrupted
>>          Version : 0
>> mdadm: unknown bitmap version 0, either the bitmap file is corrupted or
>> you need to upgrade your tools
>>     
>
> Quoting from the man page:
>
>        -X, --examine-bitmap
>               Report  information about a bitmap file.  The argument is
> either
>               an external bitmap file or an array  component  in  case  of
>  an
>               internal  bitmap.   Note  that  running  this on an array
> device
(Continue reading)

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Bill Davidsen | 2 Sep 2009 18:13

Re: Unbalanced reads of RAID10

Keld Jørn Simonsen wrote:
> On Sun, Aug 23, 2009 at 04:24:39PM +0200, Piergiorgio Sartor wrote:
>   
>> Hi all,
>>
>> some time ago I was reporting about a strange issue.
>>
>> I have a two HDDs system, with a small RAID1 (/boot)
>> and the rest as RAID10 f2 (with LVM on top).
>>
>> It seems that /dev/sdb has more reads than /dev/sda.
>>
>> I had a quick check, with "iostat", and it seems that
>> all small reads, somehow below 1~4KiB, are done from
>> /dev/sdb2, regardless.
>> Actually, it seems that only if there is a pending
>> (small) read, this will be scheduled to /dev/sda2,
>> but non-overlapping small reads seem to happen always
>> from /dev/sdb2.
>>
>> This occurs with the RAID10, but it seems also with
>> the RAID1.
>>     
>
> Hmm, have you done testing separately on each array?
>
>   
>> In normal operation, this does not seem to lead to
>> problems, but during the smart long test /dev/sdb
>> takes by far more time than /dev/sda, since each
(Continue reading)

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Bill Davidsen | 2 Sep 2009 18:27

Re: Converting ext3 to RAID1 ...

Clinton Lee Taylor wrote:
> Greetings ...
>
> I asked this question about two weeks ago
>
> http://www.issociate.de/board/post/498227/Ext3_convert_to_RAID1_....html
>
>   and have had not response, so I am going to try and re-phrase and
> hope that somebody can confirm my test case. Thanks.
>
> Wanting to convert an already created and populated ext3 filesystem.
>
> I unmounted the filesystem, ran e2fsck -f /dev/sdb1 to check that the
> current filesystem had no errors.
> Then ran mdadm --create /dev/md0 --level=1 -n 1 /dev/sdb1 --force to
> create the RAID1 device, answered yes to the question.
>   

Right here is where you invite problems. You want to create the array 
using the new device or partition, and put a new filesystem on it. Read 
and understand the man page for mke2fs in the stride= and stripe-width= 
parameters, it shouldn't matter for raid-1 but would if you use 
raid-[56]. Then mount the array, copy the data to the array, verify it, 
and then unmount the old partition and add it.
> Ran e2fsck -v /dev/md0 to check that the RAID1 device had no
> filesystem corruption on it, which it did not.
> Added a spared RAID device using mdadm --add /dev/md0 /dev/sdc1
> Then grew the RAID1 device to two compents with mdadm --grow /dev/md0
> --raid-disks=2 --backup-file=/root/raid1.backup.file
>
(Continue reading)

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Paul Clements | 2 Sep 2009 18:28
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Re: Write intent bitmaps.

Bill Davidsen wrote:
> NeilBrown wrote:
>> On Tue, August 25, 2009 12:39 am, Simon Jackson wrote:
>>  
>>> I am trying to use write intent bitmaps on some RAID 1 volumes to reduce
>>> the rebuild times in the event of hard resets that cause the md 
>>> driver to
>>> kick members out of my arrays.
>>>
>>> I used the mdadm --grow /dev/md0 --bitmap=internal  and this appeared to
>>> succeed, but when I tried to examine the bitmap I get an error.
>>>
>>>
>>> :~$ sudo mdadm --grow /dev/md0 --bitmap=internal
>>> :~$ sudo mdadm -X /dev/md0
>>>         Filename : /dev/md0
>>>            Magic : 00000000
>>> mdadm: invalid bitmap magic 0x0, the bitmap file appears to be corrupted
>>>          Version : 0
>>> mdadm: unknown bitmap version 0, either the bitmap file is corrupted or
>>> you need to upgrade your tools
>>>     
>>
>> Quoting from the man page:
>>
>>        -X, --examine-bitmap
>>               Report  information about a bitmap file.  The argument is
>> either
>>               an external bitmap file or an array  component  in  
>> case  of
(Continue reading)

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