RAID 5 question

[kikkoman]

I got a pretty cheap IBM Netfinity 5000 recently. it's gonna be used as a fileserver, so I decided to use RAID 5.

This machine has a ServeRAID 3L controller and 3x18.2 GB drives (I have one spare drive that I'd like to use as a hotspare, but atm i don't have a tray for it).
My RAID experience so far is limited to some standard onboard software RAID.

I managed to set up the array, then initialize, sychronize and finally partition it.
The win XP installer successfully loads the 3L drivers (from floppy), lets me choose the partition and actually copies the installation data to it, but after the first reboot, nothing happens.
The controller is in the first slot (which comes first in boot order, even before the onboard RAID controller), the partition is set active, I disbled all other stuff.... but it won't boot from the array.

What's wrong?
Do I have to initialize the array AFTER synchronization or what?
I'm really stuck.

[willawake]

Re: RAID 5 question

its been a while since i have installed a raid. I think you just define the array in the raid utility and then install windows pressing f6 to put your drivers. then you partition it with xp setup.

if you still have probs doing that then it would be a driver issue i guess.

[stretch0069]

Re: RAID 5 question

yeah...what will said....

i'm actually in the process of initializing a 2.4TB RAID5 that goes across 6 drives.

6 hours into it and its only 21%.

[Topcat]

Re: RAID 5 question

2.4TB? Mikey, there's something wrong with you. When it comes to raid and servers, I tend to go with data protection (mirrors). raid5 (like stripe arrays) will cause dataloss if a drive fails.

[bgavin]

Re: RAID 5 question

I don't know about the Microsoft world, but real world hardware RAID-5 will tolerate the loss of a single drive. I'm used to this with Compaq DLxxx servers and their expensive RAID controller cards.

I was thinking the Intel ICH9R controller was hardware RAID, but I guess I am mistaken. Pity. That makes Adaptec worth the cost of the card.

I've seen all the chatter about RAID horror stories, loss of array integrity, etc.... now I find out that these are software-striped, etc, RAID. No thanks.

[Topcat]

Re: RAID 5 question

I don't know about the Microsoft world, but real world hardware RAID-5 will tolerate the loss of a single drive. I'm used to this with Compaq DLxxx servers and their expensive RAID controller cards.

I was thinking the Intel ICH9R controller was hardware RAID, but I guess I am mistaken. Pity. That makes Adaptec worth the cost of the card.

I've seen all the chatter about RAID horror stories, loss of array integrity, etc.... now I find out that these are software-striped, etc, RAID. No thanks.

I say no thanks to ANY software RAID. If its not all done in hardware, I dont use it. Any RAID controller that requires a special driver to utilize RAID features is also worthless, even if the array is configured in the BIOS, it's still too 'accident prone'. Adaptec 2100S = best SCSI RAID controller I've ever used!

[bgavin]

Re: RAID 5 question

I say no thanks to ANY software RAID. If its not all done in hardware, I dont use it.

+1 to that.

[kikkoman]

Re: RAID 5 question

okay....when i said 'software RAID', i meant host RAID. I would never even touch full software RAID, but host raid is okay in some cases.

about my problem: i pretty much rule out any driver issue (since this is the only driver by IBM for the controller's BIOS/firmware version) and it's reportedly working in this exact machine in this exact configuration. sounds stupid, but it's the best approach.

my understanding is that if an array isn't initialized properly, it is recognized by the OS, but can't be booted from - no matter if the partition is set active or not.
right?

[Spacedye69]

Re: RAID 5 question

Correct. On a fresh install, you have to wait until the raid you are installing on is fully built and initialized. Once the OS is installed, you can start to build another raid and it will finish in the background. It took me a couple of times on my 2100S to get Server 2003 to take.

ps. just noticed we have spell check now! Thank GOD! I'm a moron.

[Spacedye69]

Re: RAID 5 question

TC distracted me. 3200s not a 2100s.

[willawake]

Re: RAID 5 question

i dont think we have spellcheck, you just upgraded firefox maybe?

yeh raid-5 can stand 1 drive loss
raid-6 and raid-10 can stand 2 i believe

[PCBONEZ]

Re: RAID 5 question

A full hardware RAID is a single point failure mode just like using a single drive.
The single point is just a controller instead of a drive.
If you don't have an exact replacement controller on the 'spares' shelf you'll loose the whole array.

I don't mean to be rude or anything in asking this.
Did you change the boot order in the BIOS?

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[JEWilson]

Re: RAID 5 question

Just a few cents worth

There are a number of things you can check to make sure it has been installed correctly.

1. BIOS - Does it have a SCSI Option to boot from?
This would ensure the SCSI array is booted first

2. Driver installation relevant to system partition - is FAT, FAT32, NTFS?
This is relevant so far as if the first two, OS will have intalled
MS.DOS to boot the system. If the third, will be NTDETECT, NTLDR, BOOT.INI.

Note the system partition is the actual boot loader partition and the
boot partition is where the OS resides. Both of these can be combined
on 1 partiton or kept separate. The former for me, is the best option.

Note further if disk array installed as Basic or Dynamic disks, the forner
may find these referred to as volumes.
see further http://support.microsoft.com/kb/314343/en-us

I suspect the array being HW defined would show as a basic disk if it were to boot into XP.
see further http://support.microsoft.com/kb/314470

3. ARC paths - these can be set to boot from IDE or SCSI dependent
on driver and are set in boot.ini
see further http://support.microsoft.com/kb/102873/en-us

If you have to modify boot.ini, you will need to use the recovery console
supplied with the WinXP OS media. Alternatively, you might want to try
making a boot diskette for WinXP and have a number of entries in boot.ini
to determine what ARC path is being used

If you have another XP install;
see further http://support.microsoft.com/kb/305595

Alternatively, create a boot diskette and modify boot.ini (that being so)
see further http://www.bootdisk.com/

I don't want to complicate the matter further at this juncture
Suggest review these first and then start the questions

HTH

[bgavin]

Re: RAID 5 question

A full hardware RAID is a single point failure mode just like using a single drive.

True.

Then one has to ask the question, "which is more likely to fail: Adaptec hardware or Microsoft software?"

Since the answer is patently obvious, and internet chatter about corrupt (software striped) RAID arrays is rampant, I will take the hardware risk every time.

[kikkoman]

Re: RAID 5 question

Thanks for the link on ARC paths, JEWilson. that possibility hadn't come to my mind yet.

Right now I'm low-level formatting the drives since it was pointed out on some forum that this might be necessary. strangely, you can't do that with the ServeRAID support CD, but only in DOS mode although both CD and diskette are based on ipssend (IBM's RAID management tool).

about that boot order thing:
the system has an onboard planar SCSI controller, which can be set as a boot device. the ServeRAID controller however doesn't show up in BIOS, but is in PCI slot #5, which, according to IBM, is automatically included in the boot order before the planar SCSI.

i got this whole machine for ~20 bucks, it's just for tinkering around and learning some stuff (like how the %&?! you set up a RAID5 array). nothing depends on it, and although I acknowledge that a controller can fail, I don't care in this case - a spare controller would cost LOTS more than the whole system.

[JEWilson]

Re: RAID 5 question

With the situation you describe.
A number of quick solutions may prove useful;

1. Disable the on-board SCSI (if you can).
This may make the add-on SCSI HBA visible as with ARC path scsi(0) and
not scsi (1) depending on how, if at all, it is assigned.
Note, SCSI ARC paths can complicate matters and moreso,
when you have more than one adapter.
It may be there are system board settings also which can provide you
with an answer to these issues but I confess, I am not familiar with
IBM Netfinity 5000.

2. Most modern BIOSes with BIOS extensions allows add-on
HBA, IDE-Cards and the like to be visible to the BIOS.
In situations such as these, the adpater may be seen as ARC multi(0)
etc. Than again, it may not.

3. ARC scsi is usually the last resort when you have conflicts
with BIOS enumeration, that is, getting adapter visbility in the
correct order. Then again, when you have RAID HBA redundancy
such as with 1 + 1 on the same system board there may be
no other way.

Suffice to say, having the benefit of experience with situations
such as this tends me to shy away from ARC scsi. To do this,
I make sure the BIOS and adapter are compatible in the first instance
and tend to use an IDE disk to mount the boot partitions and
and other OSes.

Recall, the system and boot partitions can be split.

All that has to be on the system partition if you format it with NTFS
is ntdetect.com, ntldr and boot.ini and set the partition active.
This is what, in effect, you would be doing with the diskette method
I referred to earlier.

The BIOS after POST will look to the active partition and NTLDR will then
parse boot.ini and, where you have multiple OS options (partitions etc.)
will present with you with the OS mount screen and load these as
required.

Of course with FAT and FAT32 it will use the msdos OS to do, effectively
the same thing.

Also, this IDE disk mount method will accomodate Linux boot loaders
such as GRUB for DOS, lilo etc.

Just a final point, be aware, Win 2K and WinXP use differing versions
of the NTFS file system, specifically, the versions of the bootloader
files ntdetect and ntldr differ. Where dual booting according to the
IDE method I have described, always use the XP system partition.
This will allows you to boot both OSes.
Also, XP allows you to use a utility called,
as I recall, bootcfg. This lets you amend the boot.ini (text file) without
having to craft it with a text editor, e.g. a util like edit is not available
in Recovery console for security reasons.

Does this help and make the matter a little clearer?

HTH

[Spacedye69]

Re: RAID 5 question

i dont think we have spellcheck, you just upgraded firefox maybe?

Yep, told you I was a moron.

[PCBONEZ]

Re: RAID 5 question

True.

Then one has to ask the question, "which is more likely to fail: Adaptec hardware or Microsoft software?"

I don't use either one. (Adaptec hardware or Microsoft software)

The cards I use store the RAID array info on the drive.
The card's firmware simply reads it from the drive and loads the info to start up the array. I can swap out cards even with a different model of the same make and the array will still work as before.

So I understand (I don't use them and only know from reading about other people having problems) a full blown hardware card stores that info in the firmware on the card similar to the way a BIOS on a motherboard does. If the card croaks you are done unless you can duplicate that stored info. As I understand it, most of the time you have to have the exact same card right down to the firmware revision to get anywhere with a recovery.

.

[bgavin]

Re: RAID 5 question

So I guess that makes Intel, Microsoft and the thousands of other high-end pro shops wrong?

I'll call them and let them know their hardware RAID and SAN solutions are subject to failure, and they should throw out those SUN and Compaq servers (and give them to me).



The possibility of drive failure is FAR higher than controller failure. You are certainly welcome to put all your eggs in a single basket (drive), but I sure will not. YMMV. On the industrial RAID controllers, I understand the array configuration is redundant, as it is present across all drives and the controller. This allows for individual drive replacement, and/or controller replacement without array loss.

RAID controller cards for industrial servers are indeed uniform. The firmware level varies, but they all have a standard process (SmartStart, et al) for maintaining a common firmware level. If necessary, card firmware can be updated to current, before hooking up the disk array. If one loses a SmartArray controller card, they will replace with same, not some after market tinker toy.

I have built hundreds of RAID servers for Intel and other big clients that I contract to. I have yet to lose a RAID controller card. Batteries yes, but that doesn't wipe out the array. What fails on the Compaq boxes with alarming regularity are the drives. I'd shit razor blades if I had that high failure rate on my small-business client drives.

Anybody running a sophisticated system without a current GHOST image has a fool for a client. Disasters occur, and loss of array configuration is one of those disasters. Restoring one from a GHOST image is a simple task.

[PCBONEZ]

Re: RAID 5 question

Bgavin, you don't follow threads very well. At least this one.

So I guess that makes Intel, Microsoft and the thousands of other high-end pro shops wrong?

I'll call them and let them know their hardware RAID and SAN solutions are subject to failure.

You do Microsoft and pro shops for support?
I'm sure they'll bill you for the service calls.
The LIKE it when their stuff breaks and they can bill you for service.

You are certainly welcome to put all your eggs in a single basket (drive)

I don't. - I never suggesting I did.
Where did that come from?

On the industrial RAID controllers, I understand the array configuration is redundant, as it is present across all drives and the controller. This allows for individual drive replacement, and/or controller replacement without array loss.

Yeah, mine do that too.
But I can swap cards without any hassles.
So in the unlikely event that the card does fail I won't have a problem getting my data back, I'm out maybe $20-25 max, and I'm finished in 5-10 minutes.

RAID controller cards for industrial servers are indeed uniform.

Only some. Card revisions and firmware changes cause major problems with servers all the time. - Google it, visit Experts Exchange..

Um,, My cards ARE used in "industrial" environments all-be-it the low end.
Although "industrial" is the wrong word. - But I know what you meant.
"Industrial" computers relates to robotics, machinery, and control systems.


"Industrial" RAID controllers are fine for some company that can afford down time and to throw boocuu bucks out the window to get someone (you for example) to come in and fix it but that situation is not acceptable to me for my own gear.
.
More is not always better and "Industrial" does not automatically make something better if it's not appropriate to the application. In fact it puts "Industrial" PROBLEMS into situations where they don't need to exist.
-
I don't want crap but I don't need a 350 horse power air compressor for my garage. A good 5 horse works just fine.

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