Latest LQ Deal: Complete CCNA, CCNP & Red Hat Certification Training Bundle
Go Back > Forums > Linux Forums > Linux - Distributions > Slackware
User Name
Slackware This Forum is for the discussion of Slackware Linux.


  Search this Thread
Old 09-17-2012, 10:53 AM   #1
Registered: Sep 2009
Distribution: Slackware 14.1
Posts: 106

Rep: Reputation: 20
Raid: Mixed drive sizes

I have had a question from the boss about mixed drive sizes in a raid system. I know next to nothing about raid so I thought I'd ask here.

We have a system that uses 160Gb drives but we can't get drives this size any more and I am wondering if we can use one or more 500Gb drives to replace any that fail. My understanding is that we can do this but that only 160Gb of the 500Gb drive will be used.

Also, if we end up replacing all of the 160Gb drives with 500Gb drives are we still stuck at 160Gb per drive or will it resize itself to the full 500Gb per drive?
Old 09-17-2012, 11:06 AM   #2
Mark Pettit
Registered: Dec 2008
Location: Cape Town, South Africa
Distribution: Slackware 14.2 64 Multi-Lib
Posts: 505

Rep: Reputation: 186Reputation: 186
Far as I my experience goes, you are correct that you can use a bigger disk in the array, but you will waste that capacity. Although if you add 2 or 3 drives that are "too big", you could in fact create a second array using just the extra capacity of the new drives.

As far as extending later when all the drives are replaced to the new bigger size (and assuming you haven't used the "spare" space), you should be able to extend the array, but it will depend on what you used to create the array in the first place (eg mdadm, hardware raid, proprietary ?).
Old 09-17-2012, 11:07 AM   #3
Registered: Aug 2012
Location: Ontario, Canada
Distribution: Slackware 14.1, LFS-current, NetBSD 6.1.3
Posts: 267

Rep: Reputation: 101Reputation: 101
Hi thirteen_engines,
You have the right idea, only 160GB of 500GB will be used, even if you replaced all the 160GB drives in the machine you will not get it to expand to 500GB automagically, depending if your raid device supports it, you would have to go into the raid setup utility and change the size of the array through its resize utility (if supported).

I cheap and dirty work around to this is to create a secondary array and move all the data off the first array then remove the first array completely then just add more 500GB drives in the place of the 160GB drives.(Most cards these days support online expansion).

EDIT: Mark Pettit beat me to it

Last edited by /dev/random; 09-17-2012 at 11:08 AM. Reason: Same answer as above.
Old 09-17-2012, 11:13 AM   #4
Senior Member
Registered: Oct 2003
Location: Bonaire
Distribution: Debian Wheezy/Jessie/Stretch/Sid, Linux Mint DE
Posts: 4,631

Rep: Reputation: 711Reputation: 711Reputation: 711Reputation: 711Reputation: 711Reputation: 711Reputation: 711
The 500 GB disks today are probably cheaper than the 160 GB when you purchased those. Especially in a business environment the entire disk is probably worth less than 15 minutes of the hourly rate.

And yes, if you don't do anything special the remainder of the space is lost. If you were using mdadm you could utilize the remainder of the space by creating additional (non-raided) partitions. For other (hardware, proprietary) systems that might be different.

And the idea of creating a new larger-sized array and copy over the data is sound as well. Any data will grow beyond the available storage anyway. And if you do so, buy some spare disks right away. That will save you the next problem.

Old 09-17-2012, 11:42 AM   #5
Registered: Sep 2009
Distribution: Slackware 14.1
Posts: 106

Original Poster
Rep: Reputation: 20

Thanks folks. This is pretty much what I thought would be the case. I didn't set up the system originally and as I said my experience with this is quite limited.

It looks like I'll probably end up setting up a second system and copying data over as you suggested. Seems the simplest approach.

Thanks again.


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is Off
HTML code is Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
Mixed permissions on backup drive Col._Panic Linux - Security 1 08-26-2006 02:08 PM
MS word pluggin mixed with gmail drive idea oudent General 4 06-30-2006 09:49 PM
sw RAID - mdadm - Almost Done! - HD sizes differ slightly Supafast Linux - General 1 07-27-2005 11:30 AM
Hard Drive Sizes Skyline General 9 07-19-2003 11:41 AM
XCDRoast -- mixed drive types DavidPhillips Linux - General 3 03-04-2002 10:20 PM > Forums > Linux Forums > Linux - Distributions > Slackware

All times are GMT -5. The time now is 01:57 PM.

Main Menu
Write for LQ is looking for people interested in writing Editorials, Articles, Reviews, and more. If you'd like to contribute content, let us know.
Main Menu
RSS1  Latest Threads
RSS1  LQ News
Twitter: @linuxquestions
Facebook: linuxquestions Google+: linuxquestions
Open Source Consulting | Domain Registration