Raid question on expanding array size

toddbailey · 12-15-10, 08:40 PM

Hi All,

I have an oppty to add another drive array and would like to know if I can do an expansion with out killing the original drive array's data.

I have 2 drive arrays, 7x 180 gb in a hardware raid 5 configuration.

Using mdadm, I've created a raid 0 drive. I then used gparted to format the array to a JFS drive
This has been working well for the last few weeks.

I'd like to know if I can safely expand the array by adding a new drive of same size (7x in a raid 5 config)

I'm running Fedora 11 x386. Each raid5 drive is 1083 gb
under mdadm the single drive is 2178gb. Will a 32 bit Linux be able to handle a 3267 gb drive / partition etc or do I need a 64 bit version to go forward?

If so how do I (safely) expand the original raid 0 array?

here is the command I used to create the original array:

mdadm --create /dev/md0 --chunk=64 --level=0 --size=max --raid-devices=2 /dev/cciss/c0d0 /dev/cciss/c0d1

And the entry from fstab to auto mount it

# compaq Raid 5+0
/dev/md0p1 /media/raid50 jfs defaults 0 2

If necessary, I could create a backup ( and probably should anyway) but it would take many days to do the backup.

Do I want to look at a 64 bit version of Fedora for the next upgrade? The latest release of Fedora has been out a while and appears to be quite stable...

thanks

drhirsch · 12-16-10, 07:38 AM

This question ist very offtopic.

In short:

You do not need a 64 bit linux to access disk drives beyond 2 TiByte. Maybe you are confusing Tera (~ 2^40) with Giga (~ 2^30)? Anyway, disk accesses have been 64 bit addressable for ages in linux on 32 bit architecures.

There is no way I am aware of to exent a raid 0, besides backp and recreate. I am pretty sure it can't be done because of the way the data is striped accross the two drives.

12-15-10, 08:40 PM	#1
toddbailey Registered User Join Date: Jul 2007 Posts: 12	Raid question on expanding array size Hi All, I have an oppty to add another drive array and would like to know if I can do an expansion with out killing the original drive array's data. I have 2 drive arrays, 7x 180 gb in a hardware raid 5 configuration. Using mdadm, I've created a raid 0 drive. I then used gparted to format the array to a JFS drive This has been working well for the last few weeks. I'd like to know if I can safely expand the array by adding a new drive of same size (7x in a raid 5 config) I'm running Fedora 11 x386. Each raid5 drive is 1083 gb under mdadm the single drive is 2178gb. Will a 32 bit Linux be able to handle a 3267 gb drive / partition etc or do I need a 64 bit version to go forward? If so how do I (safely) expand the original raid 0 array? here is the command I used to create the original array: mdadm --create /dev/md0 --chunk=64 --level=0 --size=max --raid-devices=2 /dev/cciss/c0d0 /dev/cciss/c0d1 And the entry from fstab to auto mount it # compaq Raid 5+0 /dev/md0p1 /media/raid50 jfs defaults 0 2 If necessary, I could create a backup ( and probably should anyway) but it would take many days to do the backup. Do I want to look at a 64 bit version of Fedora for the next upgrade? The latest release of Fedora has been out a while and appears to be quite stable... thanks

12-16-10, 07:38 AM	#2
drhirsch Registered User Join Date: Jul 2005 Posts: 61	Re: Raid question on expanding array size This question ist very offtopic. In short: You do not need a 64 bit linux to access disk drives beyond 2 TiByte. Maybe you are confusing Tera (~ 2^40) with Giga (~ 2^30)? Anyway, disk accesses have been 64 bit addressable for ages in linux on 32 bit architecures. There is no way I am aware of to exent a raid 0, besides backp and recreate. I am pretty sure it can't be done because of the way the data is striped accross the two drives.