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Is it safe or reliable to incorporate multiple RAID Configurations on a Server such as this:

RAID-1: Main Drive OS

RAID-5: Storage Drive (Engineering Projects)

RAID-5: Storage Drive (Engineering Projects & Software)

2 - hot swap drives for each of the RAID-5 Configurations

Server will be used as Giant File Server with a Few Engineering License Managers running on it.

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  • What type of hardware? What type of RAID controller? How many disks?
    – ewwhite
    Mar 26, 2012 at 22:05

2 Answers 2

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Assuming this is all managed by a hardware raid controller; then yes it is safe and reliable. Make sure you also have a backup plan in place including off-site storage if possible for business continuity. More information would be helpful to include the server make/model and RAID controller used.

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    Would it not be "safe and reliable" with software RAID?
    – EEAA
    Mar 26, 2012 at 23:00
  • Just like hardware raid, software raid has behavioral quirks that can make it inappropriate or difficult to use under some circumstances. For example, older Linux distributions can't boot off a software RAID at all, while newer ones can usually boot off of a software RAID only when it's a RAID 1.
    – Charles
    Mar 26, 2012 at 23:07
  • That is a very good question. I would say yes but it's dependent on many factors, not the least of which is the sysadmins knowledge and capabilities. I think, and this is just my opinion, that many sysadmins consider hardware RAID a better choice if for nothing more than simplicity.
    – murisonc
    Mar 26, 2012 at 23:27
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    @murisonc, when high performance is not a major requirement I generally find a software raid to be more simple to work with. Since I know I will still be able to use my drives if the RAID controller fails. Or I can easily migrate them to other hardware.
    – Zoredache
    Mar 26, 2012 at 23:31
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    @Charles, modern Linux distributions can boot from much more than RAID 1. I've put root filesystems on encrypted LVM on RAID-5 and it works fine. The /boot directory needs to be on a plain partition or RAID-1, but that can be a small partition of its own, with the rest of the drive being one big partition that's used as a RAID component.
    – Wyzard
    Mar 27, 2012 at 0:47
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You've made no talk of hardware or software, so its difficult to discuss specific issues, but there's no fundamental reason why you cannot mix and match different types of RAID on the same server platform.

In fact, its quite desirable to do so; its quite a common configuration option for some types of server to contain different types (speeds/capacities) of drive, striped in different ways, for different tasks (note I'm NOT talking about having different speeds of drive or so-on in the same RAID container/group/set/bunch of disks, but of having more than one RAID group)

On a database server, for example, DB log files might need very fast write speed above all else, and so you'd choose a RAID system that favours that; main database files may require a more balanced choice between read and write so again, you'd choose a RAID system that gave you that, DB backup files could be saved to slower/cheaper/higher capacity drives, etc.

In the example you describe, again its not that unusual to have different RAID sets that are home to totally different sets of data on a file server.

Of course, if you do this then you've made it much more complicated to maintain the hardware platform - its no longer enough to know that "one drive" has failed, you need to know which one, and which raid group its in.

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    If "one drive" has failed, you always need to know which one it is, so you know which one to replace.
    – Wyzard
    Mar 27, 2012 at 0:50
  • Sorry @wyzard if I wasn't clear - you'd need to be sure of what type of drive to use for a replacement in the event of a failure when you have multiple types of drives in play, as opposed to just needing to replace 'a drive' in a system where the disks were all identical.
    – Rob Moir
    Mar 27, 2012 at 5:25

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