5 Disks - 1 RAID array or 2??

[maxrebo]

Hi, Just setting up a new server with 5 disks andim wondering if any one would advise setting it up with 2 arrays or 1

Maybe 1 array as RAID 1 (for the OS) and the other as a RAID 5 (for the data)

Or just a RAID 6 for all 5 disks?

What does everyone else do?

 

Regards

[Norphy]

What size are the disks, what speed and interface? What raid controller is in the server? More than that, what are you going to use the server for? There is no right answer and 5 people will give six opinions but to form those opinions it would be helpful to have more information. Edited May 10, 2015 by Norphy

[maxrebo]

What size are the disks, what speed and interface? What raid controller is in the server? There is no right answer and 5 people will give six opinions but to form those opinions it would be helpful to have more information.

thanks for the reply,

5 x 1Tb, 10k SAS disks.

Raid controller in the Dell H730 (i think).

I Realise everyone does things their own way just maybe how they\you have set it up in a similar situation

 

regards

[snagrat]

I wouldn't RAID 5 with just 3 disks,

 

I would RAID 6 as you suggest

[mrbios]

Whats the server actually for?

[MordyT]

I have personally started recommending one array in almost every case. You can partition in windows however you want and there is little to gain by having separate VDs. A 5,6, or 10 will recover from a disk failure no problem just as easy if it is one VD as it will if it is 2.

 

There is benefits to having one array, for example your hot spare is much more useful, adding disks and expanding partitions is much more clean, m management is easier, etc.

[tmcd35]

How much total disk space do you require?

 

RAID10 = 2Tb + 1Tb (Hot Spare?)

RAID5 = 4Tb

RAID6 = 3Tb

 

If you want performance and reliability and are not pressed for space then go RAID10+HS.

If you need the space go RAID5.

If you don't care about speed and are paranoid about possible drive failure but need more than 2Tb, RAID6.

[dhicks]

Raid controller in the Dell H730 (i think).

 

With 1GB of cache RAM? We have a similar MegaRAID SAS 9271-8i with 1GB of cache in a couple of our Dell PowerEdge R510 servers. We have 4 4TB disks in a RAID5 array in each server. A discussion on performance can be found in here, but my basic conclusion is that for small enough read / write workloads, a RAID 5 or 6 array with a 1GB on-controller cache seems to perform as well as an array with SSD drives available for caching. In our case, a "small enough" workload means the file server is capable of handling general file access (redirected home folders, shared file areas for office documents and images) for at least 100 simultanious users. Due to an issue with our backup script, at one point we were copying all files from the main file server to the backup server every day as well as being a general file server, and we found we started hitting problems with around 80 users logged on.

 

Your RAID controller supports JBOD mode, so you could go for a Windows Storage Spaces volume, if you're setting a Windows server.

 

Quick edit: Just thought - both those servers have a decent amount of RAM in, 64GB, some of which is also available as a cache for Windows file services. The all-files-being-constantly-read error probably rendered the Windows file buffer useless, so the 80-ish simultanious users figure is probably valid for a Windows file server with very little RAM, in practice a file server with a decent bit of RAM should probably handle more users.

Edited May 11, 2015 by dhicks