Adding disks to a raid 5?

[SuNe^]

Is it in someway posible to have a raid 5 where you can add disks after each other without having to reformat the raid and make a new one?

[LinusTech]

High end RAID controllers will support this kind of functionality. Have you looked into ZFS at all?

[SuNe^]

High end RAID controllers will support this kind of functionality. Have you looked into ZFS at all?

I dont know anything about raid and so tbh, basicly all i know is for safey raid 5/6 is the best and thats it.

I google some, but says diffrent everywhere more or less, some say you can some say u cant..

Also happy Canada day or what you say =)

 

 

 

 

Edit; Could someone please link a raid card thats able to do what i asked for and supports 24 sata disks?

Been searching for over an houer now and i cant find anything  :mellow:

[IdeaStormer]

I will toss in "no". If you are asking us and haven't read your RAID controller doc, well you're bound to be needing to re-do your RAID array in short order.

[madcow]

Linux mdadm allows you to add disks too. I've expanded my raid probably 10 times now without a single issue. I also recommend the M1015.

[IdeaStormer]

Linux mdadm allows you to add disks too. I've expanded my raid probably 10 times now without a single issue. I also recommend the M1015.

 

Be helpful and provide a link to your informative post(s).

[h264]

High end RAID controllers will support this kind of functionality. Have you looked into ZFS at all?

 

This functionality is usually called Online Raid Expansion.  Also some cards have the ability to change the TYPE of raid on the array, which is called Online Raid Migration.  Linus is correct though, you'll need a filesystem that supports online resizing once the process is complete, like ZFS or XFS.

 

Also I can personally attest that's it's a pain in the ass and takes forever on larger volumes.  If you're not worried about availability (say, like running a web-service or something for a business), you're probably better off just backing up your stuff, wiping the array, and expanding it that way.

[Eric1024]

ZFS actually does not support adding disks to an array in order to expand it after you've created it from what I understand and from my experience with it. You can use it to add disks to the same zpool, but not to the same raidz array. In other words, if you had 4 drives in raidz (raid5) and wanted to expand your capacity, you'd either need to replace every drive with a drive of a larger capacity, or you'd need to add another 3 or 4 or more drives to the zpool to create another raidz array.

That being said ZFS in an awesome file system. If you want me to go into more detail about it I can, or you can read about it here:

http://en.wikipedia.org/wiki/ZFS

http://pthree.org/2012/04/17/install-zfs-on-debian-gnulinux/

And to answer your original question, with many implementations you can not expand a raid 5 array. The exceptions that I know are: hardware raid controllers that support OCE (online capacity expansion, which is rather dangerous IMO in that if you have a power outage you can potentially loose everything), and linux mdadm, both as previously mentioned.