0

This is bit of a follow on from my previous question us HP Smart array.

Is it possible to RAID a single ssd? What setting will need to give it?

What benefits will I have?

3 Answers 3

2

No, you can't raid a single SSD. You need at least 2 drives for the simplest raid level - 1 or 0. There would be no real benefits from running it as a raid, tho a raid card may let you use drives with a SAS interface, or have other useful features even when used with JBOD or single disk layouts.

6
  • I assume it will also be a no to running 1 hdd as a raid to then? I have a a microserver and when sata config set to smart array both ssd and hdd are unassigned and undetectable. Guess I'll have to use sata legacy configuration. Aug 28, 2015 at 6:18
  • Sata AHCI Support should be the correct option for a modern OS
    – Journeyman Geek
    Aug 28, 2015 at 6:21
  • I was just going to install ESXi on my ssd and have all storage on the single hdd for now, would you still recommend sata AHCI? Aug 28, 2015 at 6:31
  • Absolutely. That said, if I recall correctly, esxi's tiny and you won't really need all the space on the SD card. Its fairly routinely booted off USB keys and such.
    – Journeyman Geek
    Aug 28, 2015 at 6:33
  • 1
    Its seriously worth looking up the differences between these properly - basically for anything after windows 7, modern linux releases and generally anything not really old, AHCI is the 'right' answer. Consider sata legacy for things like XP, which are too old. I believe ESXi on HP microservers is fairly common, so you ought to be able to easily find documentation on the setup with a simple google search.
    – Journeyman Geek
    Aug 28, 2015 at 6:49
0

RAID stands for redundant array of inexpensive/independent disks. This is a clue that a single disk will have no benefit whatsoever.

However, should you decide to get a second disk an have a RAID set up, I wouldn't use a software RAID solution anyway.

0

Is it possible to RAID a single SSD?

It is not possible to assemble an array of multiple disks with a single disk.

You can connect a single disk to a RAID controller and use the JBOD setting. That will treat it as a single disk. So you can use a single drive. It just will not be part of a RAID array.*1

What setting will need to give it?

  • If you just want to access the disk on a hardware RAID card sunch as the HP Smart array then use the JBOD setting.
  • If you run software RAID (e.g. mdadm on Linux) and you intend to add a second disk later then you could create a mirror between two devices. One device would be the SSD, the other device would be missing.

    Example
    mdadm --create /dev/md0 --level=mirror --raid-devices=2 /dev/sdb1 missing
  • Of you have an ICHR or similar chipset and you use Intel fake RAID then you can set the controller to RAID with a single disk. It will not give you any benefits unless you want to add a second drive later without changing the drivers.

What benefits will I have?

With a single disk: No benefits.


As others already posted: Many servers have an internal SD card reader. It is not uncommon to install the hypervisor on that and keep a spare card with a backup.


*1: Nitpick, in theory you could use mdadm to create an array from multiple partitions. That would result in all the bad parts and none of the benefits of RAID, so no sane person does that.

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .