Optimal use of two SSDs in a Linux webserver without a hardware RAID controller?

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smartup2014-05-16 13:26:30

linux

smartup, 2014-05-16 13:26:30

Friends, there is a server (yes, from Hetzenra) with a pair of SSDs and no hardware RAID controller. The server is planned for web hosting (several dozen sites), CentOS will work on it. There are no plans to buy hardware RAID.
What do you think, is it worth doing software RAID? Or is it better to just scatter the load across the disks (base on one, static on another)?

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5 answer(s)

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Igor, 2014-05-16
@merryjane

RAID in any case is necessary. The server must be at least minimally fault tolerant in terms of disks.

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Nikolai Vasilchuk, 2014-05-16
@Anonym

RAID will be more reliable and faster.

A

Alexey Lesovsky, 2014-05-16
@lesovsky

definitely RAID1. so that later there were no headaches with the restoration of lost sites.

P

Puma Thailand, 2014-05-16
@opium

it is logical that two of them are put there in order to roll raid1 on them by default, there is not much to think about here.

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igor2503, 2014-05-18
@igor2503

The answer is not so clear. It is necessary to assess the risks of failure of specific parts. Also, one should not forget that modern SSDs are already a raid, not a mirror of course, but they will correct some of the errors.
1) a software raid (mirror) will save only one of the SSD electronics from failure, and the probability of this is low (read about "but" below). More precisely, approximately the same as the failure of memory or CPU. It's already simple. From the wear of the flush will not help. It makes sense to do raid0 only to increase access speed, if necessary.
2) another point, some of the errors (not big) are glitches of the operating system. Windows does more of this (but everything happens), resets the dump to the beginning of the disk and litters everything in the world. A raid (mirror) will not help at all. Here it is better to divide the data into two disks and regularly backup to an adjacent disk. And generally a regular backup.
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And most importantly, will anyone serve this thread. Actually, this is where you should start. If this is done and given to the client, and there is a possibility that they will never look at smart again, then you can’t save on hardware. Hardware raid is MANDATORY + server SSD disks + regular disk for archive. It is also worth doing if the project already "has" a cost and idle time is not acceptable.