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Doubts on creation of arrays.

Daniel Bareiro
Occasional Advisor

Doubts on creation of arrays.

I'm using a Proliant DL380 G5 - E5405 with a SmartArray E200 controller and when I trying to create a new logicaldrive with two discs in RAID 1 I cannot use this level. The unique levels available are 1+0 and 0. Which can be the cause by which it does not appear level 1?

On the other hand, after to have created the array of level 1+0 with discs in bays 6 and 7, I only see activity on LED of the disc in bay 7. The one of bay 6 is off. The same happens putting another disc in that bay. This behavior is ' normal' with this level of RAID?

Thanks in advance.

Regards,
Daniel
6 REPLIES
Matti_Kurkela
Honored Contributor

Re: Doubts on creation of arrays.

"1 + 0" just means that you can, at your option, expand your RAID set later by adding extra disk pairs. When you have only two disks in your RAID set, 1 + 0 is equivalent to RAID 1. It only becomes a true RAID 1 + 0 with four or more disks.

After creating the array, the controller will be copying the data from one disk to the other. This happens "in the background" while you can install the OS.

If the disk in bay 6 is the source disk of the copy operation, the controller will only read from it, while the disk on bay 7 will get write + verify operations = more work. Maybe the individual read operations on disk 6 take so little time the LED does not have enough time to light up properly? Or the LEDs might only indicate write operations?

MK
MK
Daniel Bareiro
Occasional Advisor

Re: Doubts on creation of arrays.

Hi Matti.

Thanks for the explanation on RAID 1+0. I consider that you speak of "pairs" because is RAID 1+0, is it correct? Because with RAID by software in GNU/Linux I could create a RAID 1 (although concerning partitions) with three discs, for example.

The OS was installed on an array with logicaldrive with RAID 5. The RAID 1 was created later to the installation of the operating system.

This is the configuration for my RAID 1+0:

array B (SAS, Unused Space: 0 MB)

logicaldrive 2 (136.7 GB, RAID 1+0, OK)

physicaldrive 2I:1:6 (port 2I:box 1:bay 6, SAS, 146 GB, OK)
physicaldrive 2I:1:7 (port 2I:box 1:bay 7, SAS, 146 GB, OK)


That logicaldrive is referenced by the /dev/cciss/c0d1 device of the OS that has the following partitions:

# fdisk -l /dev/cciss/c0d1

Disk /dev/cciss/c0d1: 146.7 GB, 146778685440 bytes
255 heads, 32 sectors/track, 35132 cylinders
Units = cylinders of 8160 * 512 = 4177920 bytes
Disk identifier: 0x40bfcf59

Device Boot Start End Blocks Id System
/dev/cciss/c0d1p1 1 2452 10004144 83 Linux
/dev/cciss/c0d1p2 2453 35132 133334400 83 Linux


Mounting the /dev/cciss/c0d1p1 device previously formatted with ext3 and making a copy of several archives in it, activity in the led of the disc of bay 7 is only observed. The same happens during the reconstruction if I remove the disc of bay 6 and I return it back to its bay.


Thanks for your reply.

Regards,
Daniel
Matti_Kurkela
Honored Contributor

Re: Doubts on creation of arrays.

Yes, you're correct about RAID 1+0 and disk pairs.

Hmm... If the LED of the bay 6 disk does not light up even when you remove & replace that disk (and thus trigger a RAID auto-rebuild on that disk), the LED seems to be faulty.

I don't have any of the newer 2.5" SAS disks handy at the moment, but at least with the older 3.5" SCSI hot-swap disks, the actual LEDs were in the backplane of the hot-swap disk bay. The disks just had clear plastic "light-pipes" to guide the light of the LEDs to the front panel of the disks.

I think the LEDs on the 2.5" disks use a similar design, but I cannot verify it right now. If so, the activity LED of the bay 6 might be out of alignment, damaged or blocked somehow.

If a visual inspection (& cleaning if necessary) of the disk backplane LEDs does not help, and the server is still under warranty or on a hardware support agreement, you might talk with a HP engineer about exchanging the disk backplane at some convenient maintenance break.

I would rate a broken disk activity LED as a "cosmetic problem - no significant impact on the use of the server". But if the warranty or a support agreement allows you to have it fixed for free, that's nice.

MK
MK
Daniel Bareiro
Occasional Advisor

Re: Doubts on creation of arrays.

Hi Matti

Happy new year! :-)

About RAID 1+0, well, but I have understood that the SmartArray E200 controller also supports RAID 1. Then why it can be that I has not seen that level when trying create a new logicaldrive? It is a simple curiosity. What conditions would have to fulfill to create a raid 1 (not 1+0)?

The Proliant is a practically a new equipment, so it is in warranty. Whatever happens, before I would like to test the following thing:

* Remove the spare disc of the RAID 5 with hpacucli. The LED of it seems to behave of normal way. That is to say, it only has activity when it is added to the RAID either during a reconstruction or like after it.

* Remove the disc that was spare of its bay.

* Remove from its bay to the disc of the RAID 1+0 whose LED does not light up. This would have to leave to RAID 1+0 in state of 'Interim Recovery Mode'.

* Put the disc that was spare in the bay that is available of RAID 1+0. This would have to initiate an auto-rebuild.

If even so the LED follows without having activity, then the problem would be limited some component of backplane, according to what you said.


Thanks for your reply.

Regards,
Daniel
Daniel Bareiro
Occasional Advisor

Re: Doubts on creation of arrays.

Hi Matti

Investigating the specifications, this controller only seems supports RAID 0/0+1/5 but does not support RAID 1. Is it correct?

These are the data of the controller:

# hpacucli ctrl slot=3 show

Smart Array E200 in Slot 3
Bus Interface: PCI
Slot: 3
Serial Number: PA6C90N9SW7073
Cache Serial Number: P9A3A0B9SWK8P5
RAID 6 (ADG) Status: Disabled
Controller Status: OK
Chassis Slot:
Hardware Revision: Rev A
Firmware Version: 1.72
Rebuild Priority: Medium
Expand Priority: Medium
Surface Scan Delay: 15 sec
Cache Board Present: True
Cache Status: OK
Accelerator Ratio: 50% Read / 50% Write
Total Cache Size: 128 MB
Battery Pack Count: 1
Battery Status: OK
SATA NCQ Supported: False


On the other hand, as I commented, I removed the disk in bay 6 and put spare of RAID 5 in that bay, and during the reconstruction the LED vdid not light up either. This would reinforce the theory that the problem is in backplane.

Also I confirm to you that the disks have two light-pipes for the illumination in the frontal panel.


Thanks for your reply.

Regards,
Daniel
siny
Occasional Advisor

Re: Doubts on creation of arrays.

RAID1 - defines mirroring for two hdd (requires two hdd)
RAID0 - defines striping of data across one or more hdd. (requires min 1hdd)

RAID1+0 - defines the mirroring of two sets of RAID1 array and then the striping of data for two hdd to overcome the physical drive size capacity limitation.

eg. RAID1 bay1 (data ABC) -> bay2 (data ABC)
eg. RAID1 72gb x2 = 72gb effective space

eg. RAID1+0 72gb x4 = 144gb effective space
bay1 (data ABC) -> bay5 (data ABC)} RAID 1
(writing across bay1 to bay2)} RAID 0
bay2 (data DEF) -> bay6 (data DEF)} RAID 1

SmartArray supports RAID1, RAID1+0, RAID0, RAID5.

RAID1 = HP RAID 1+0 (hp context)

If you plug your bay6 to any other bays and the led returns, the hdd light pipes are working.

Regards