RAID write penalty

dnwk

What's the software RAID 5 penalty on performance compare to no raid?

rajprakash

WAT?

Edit: OP reworded post to make more sense

wojons

I think he is asking about the raid 5 and raid 6 wrote whole problem caused by having parity drives

GoodHosting

RAID5 has a serious write penalty, you are basically slowed to the write speed of your parity disks or parity array (if you have an advanced RAID setup where parity is set up on an explicitly separate RAID array.)

I would not recommend it, perhaps RAID50 ; for data you plan to read a lot, but not to write to very often.

Backupsy uses RAID50 iirc @serverian .

dnwk

I have 3 1TB hard drive. I use to run system on 1 hard drive with no raid and data on the raid 1 of other two hard drives. Not sure any better raid configuration could be without adding new hard drive.

GoodHosting

@dnwk said:
I have 3 1TB hard drive. I use to run system on 1 hard drive with no raid and data on the raid 1 of other two hard drives. Not sure any better raid configuration could be without adding new hard drive.

My personal recommendations:

• RAID is required if you are hosting customer data. If you are hosting only personal projects, you should still RAID if possible (at least RAID1. You can do this for 3 drives, albeit it's a bit wasteful and a bit of a nutcase to set up and maintain. RAID5 (or 6? Forgot which one) would give you a dedicated parity disk, which you don't want in this case either.)

• Always make backups of everything you hold dear, those backups should be off the server (such as on your own computer, thumb drive, cloud storage, HubiC, Box, or perhaps all of the above and more. I recommend Backupsy by @serverian for this kind of thing.)

Sadly, 3 drives leaves you with very little options. 4 Drives gives you RAID10 (the best of RAID in my opinion, as it gives you a fairly consistent write speed; and great read speeds; as well as giving you redundancy enough to allow up to two drives to fail (although you wouldn't want to push it, since if the wrong two fail; you lose everything.)

drserver

Can i ask what are you hosting on that server ?

dnwk

GoodHosting said: RAID5 (or 6? Forgot which one) would give you a dedicated parity disk, which you don't want in this case either.)

That's RAID 4