How to increase storage space in a RAID 10?

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So Lets say that I have a server running on 4 hard drives... We have them in a RAID 10 setup and they are all 600GB. Now I take one of them out, then swap it physically with a 1.2TB HDD. In this circumstance, obviously the larger drive will be limited to the amount that its mirror/striping buddies have, but when I let the drive repopulate with data from the mirrored drive, then replace the mirror and let that repopulate on another 1.2TB, then I do the same with all of the other drives, will the RAID update to the larger size when the larger size is available on all drives, or will I need to just back it up from the 600GBs and shut everything down and flash it to the new ones? I know, its kinda a more advance question, but I am supposed to be updating my server storage space, and I have no idea if this shortcut would work or not. I dont want to waste company time trying it though unless it has a possibility of working.

user865814

Posted 2018-01-25T00:34:54.720

Reputation:

No, the RAID array will not magically use the additional space. There has to be a way for you to tell it to "grow" to use the space. I am not away of a software RAID 10 that can do so. So this is a build-a-new-array-then-copy-the-mirror/image over" endeavor. See Slartibartfast answer or develop your own plan. – Damon – 2018-01-25T04:02:46.003

Working on imaging now. However, It is a hardware RAID. Its all BIOS baby. If that changes your answer, then it would be worth trying. hahaha. – None – 2018-01-30T20:29:21.067

Answers

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The responsible thing to do is shut down, image, test the image, build the new array, restore from the image, start up the new system.

However, if Windows / your RAID hardware (software?) will let you create a broken array, and if the array is split by drive, then you could conceivably:

  • Image the system (this way you fall back to the better answer)
  • Pull the correct two drives so that you effectively have a single RAID0 array (no redundancy)
  • Add two larger drives (why 1.2TB when you can get much bigger?) in a new RAID10 array that is non-redundant (only 2 of 4 drives, effectively another RAID0)
  • Image from smaller to larger.
  • Pull the two older, smaller drives.
  • Install two new, larger drives.
  • Add the two new drives to the new array and have the system rebuild it.

That said, don't do it. It will be much easier to fall back to your original 4 disks if you don't play silly tricks. Presumably you have RAID10 for a reason, and part of that reason is reliability.

Slartibartfast

Posted 2018-01-25T00:34:54.720

Reputation: 6 899

"why 1.2TB when you can get much bigger?" Probably because they are SAS and most larger drives that are SAS are expensive comparatively to larger non-SAS drives. Especially if you do not need the additional space. And RAID 10 is extremely fast and robust, more so than RAID1. eg 4x600GB is generally "better" than 2x1.2TB. – Damon – 2018-01-25T04:06:02.890

The 1.2TB is because this is the largest compatible HDD for my server. The server is an HP Proliant Gen 8 Rack server. It has limited choices as far as storage and it just so happens that the largest compatible drives for the server are that size. We would have gotten 2 or 3TB HDDs but they were not an option. We do need the additional space, as we have already completely filled the 8 600GB drives for a grand total of 2.4TB of data and again that is redundant, so its actually 4.8TB. I would have loved larger drives. hahaha. – None – 2018-01-30T20:27:33.207

Asked: 2018-01-25T00:34:54.720

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Active: 2018-01-25T03:22:27.383