Adding Hard Drives to an exsisting RAID 5 array

I have a server that has four 80 GB hard drives set up in RAID 5....in 2 partitions C and D.  C being OS and D being data to include exchange stores.  I want to add 3 more 80 GB hard drives and one hot spare.  These are dell poweredge 2900, SBS 2003 and i am useing the PERC 5/i Raid controller.  I believe that this setup supports adding these disks while the machine is up and running.  I also believe that i can add these three disks through Dell's open manage software.  Can i allot these this added disk space right to the D partition thought open manage without having to move data around?  I did buy Paragon Partition Manager so i do have a third party software package if need be.  What do i need to do prior to adding these disks?  I know i should take a full backup.  I am using backup exec and it seems to not want to backup my mailbox stores, what is the best way to back those up/get a full backup?  Lastly how do i set up a hot spare?    
techitch2Network AdminAsked:
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DavidPresidentCommented:
You need to kick off a data consistency check/restore.  This makes sure that there are no parity errors lurking.  (Note, this is run within the RAID controller, not a windows scandisk).

Also, update firmware/drivers.

Finally, do not make C & D on same disk drives.  By doing that, you kill performance.  Every disk I/O you do on C slows D down and vice-versa.

What is best way to backup??  Take the opportunity first to just build a 2-drive RAID0 temporarily as proof of concept, then do a backup of "C" onto the 2- disk RAID0 to test to make sure you can successfully boot it.

acronis has perc drivers, but you need to test.  

Yes you can add disks

Tell RAID controller at BIOS (but they also have a utility you can load and use under windows) that the new disk(s) are hot spares.

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charlestasseCommented:
The Perc 5 Raid Controller supports Reconfigure of the Raid 5 allowing you to add the drives directly to the Virtual Disk.
You must have Open Manage Server Administrator - ftp://ftp.us.dell.com/sysman/OM_6.2.0_Man_Node_A00.exe
Make sure you take the custom install and ensure that the storage module is being installed.
Open Manage will also allow you to select a specific drive and make it a hot spare
Once you have completed the Reconfigure of the array you will need to use your 3rd party app to extend D: into the new unallocated space. To see this new space you may need to rescan the disks from within Disk Management
techitch2Network AdminAuthor Commented:
I knew asking this question would bring you here dlethe.  Listen, I've been running C and D across four disks for 5 years now.  This machine has SQL and exchange running on it.  Our performance seems pretty good just getting low on drive space. The data consistency check and restore.....this is run from boot correct?  What if there are parity errors?  Is this a long process, like something i could do over night?  
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DavidPresidentCommented:
Checking / repairing XOR errors should be run on regular interval.  Let's say for sake of argument that block #0 on the first disk becomes unreadable while system is running.  Then disk 1 fails.   Quite simply, you won't be able to boot the machine.

People fail to realize that there are 2 benefits for the parity protection that RAID1/5/10 gives you.  Sure, you are protected against a drive failure, but ONLY of all the blocks are readable on all the surviving disks.  If the example machine still had all of the disk drives, and tried to rebooted.  Then the RAID controller would have detected the unreadable block, and automatically extrapolated the correct value from the redundant RAID XOR data, remapped the bad block, and written the correct value.

A RAID consistency check (or repair or verify, whatever your particular controller calls it), reads all blocks on all disks, and correct these errors.  one is NOT protected against data loss on a drive failure unless you have no unreadable blocks on the surviving disks.   Furthermore, depending on the HDDs you use, it could take several seconds to 10+ seconds for a controller to repair a bad block.  Better to have that done at 2 AM instead of when users are pounding it

Most controllers have a native O/S utility that let you run this while your O/S is booted. The better controllers let you prioritize how it runs, and the best controllers do this automatically in background 24x7 with near-zero impact.  The cheap ones require you to run it from BIOS.   Obviously, if you run it from BIOS then the system is offline, but it will run much faster because it doesn't have to worry about background I/O.  Just run it from whatever mode is "best" for your environment.  

A parity error is the boolean logic XOR calculation.  To make it simple, lets' say the parity operation is addition, since everybody can do this.  You have a 3-disk RAID, your data is "A", "B", and parity=A+B.

If you lose block A, or the entire disk, then the raid engine can extrapolate the value A, because it has B, and the parity value "A+B", so it subtracts to give you "A" and fakes it all out.   Same if you lose "B", and if you lose parity, then no problem either.

but if A is unreadable because you never do data consistency repairs, and then you lose B or A+B, then you end up losing data in the same way as if you lose 2 of the 3 disks in your RAID5.  Granted you didn't lose C, D, C+D, so loss is limited, but in this case that one block prevents your system from booting.  No block 0 or block 1, and your system is useless.
charlestasseCommented:
techitch2:
There is a good chance that you are already running a consistancy check as this is a normal function of the controller. If you were to read the controller log file it would show you that ever week or so it is doing a patrol read.
Frankly for what you are wanting to do, I do not see the necessity of running a full consistancy check, but what the heck, it can't hurt anything.
DavidPresidentCommented:
Yes, like I wrote premium controllers have ability to automate regular consistency operations.  They also have the ability for somebody to disable this feature, or set the priority so low that it never completes. Best practice before messing with any RAID config is to initiate such an operation and confirm it runs to completion.   Also take the opportunity to upgrade firmware/drivers as PERC controllers, as LSI adds firmware updates every few months, so that has to tell you that important fixes come out regularlly
charlestasseCommented:
Current Driver and Firmware for 2900 / Perc 5/i

PERC 5/6 RAID controller driver 2.24.0.32 for Server 2003 32bit, released 6/30/09, recommended, urgent if yours is less than 1.21, *DON'T reboot, do firmware next: http://ftp.us.dell.com/SAS-RAID/RAID_DRVR_WIN_R211422.EXE 
 
PERC 5/i RAID controller firmware 5.2.2-0072, released 10/7/08, urgent if yours is less than 5.1.1, Windows update package, *Choose NO to reboot to perform next update: http://ftp.us.dell.com/SAS-RAID/RAID_FRMW_WIN_R189337.EXE 
 
techitch2Network AdminAuthor Commented:
Wow this info is great guys.  I'd have to say some of the best i've gotten on this site.  I am going to preform your suggestions during the week here and i will award points.  I may be drilling for more info as i move......keep it coming!
techitch2Network AdminAuthor Commented:
dlethe....should i add disks before or after parity check?
DavidPresidentCommented:
Do parity check, then add disks, then do another.  You never want to rock the boat w/o knowing it is clean.  For example, one of the disks you add could cause a short and take out another disk.  If you have 100% consistent data, then you have much lower risk of data loss when something goes bad.
techitch2Network AdminAuthor Commented:
I did a parity check.......all is well.  Thanks for the info.
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