I have my HP 2012 FC San which I have had for a while. At the time I bought it with 5 SATA disks to keep the cost down. This has been configured in RAID 5 with 2 hot spares (Did have one hot spare but when one went I bought and extra as well). This has been storing our user files and application source points.
We are moving to server 2008 from 2003 over the summer and I will be implementing about 75% as VMs.
I have treated the san to 7 new 15k SAS disks so I have
7 X 15k SAS Disks 300 gig
5 x 7.5K SATA Disks 450 gig
My main data volumes will be:
Staff User Data (100 users) 100 gig
Student User Data (750 users no more than 250 in use at once) 150 gig
Media Courses storage (Movies flash etc for ICT iMedia) 50 gig
Common area (Used for all staff resources, mostly office docs and some movie clips etc) 150 gig
Admin Storage (only for admins special apps and storage, hardly used) 100 gig
Virtual Machines 2 x DCs,File Server, DPM Server(Storage for this may go on an Openfiler box I am thinking of implementing), SCCM server, Print server. SIMs will be on it's own physical machine and we wont have Exchange after the upgrade.
So given this set up what should I put on the slower set and what on the faster set and what raid level shall I use bearing in mind I will need hot spares.
Obvious ones are:
VMs on SAS
Admin Storage SATA
I guess I am just wondering what others will be ok on the SAS disks without degrading the performance of the VMs. Also RAID levels as previously mentioned 5,6,10 etc? I realise I will lose a lot of storage with some of these RAID types so I am just looking for the best balance.
SAS if room left - Staff User Data (100 users) 100 gig
SAS - Student User Data (750 users no more than 250 in use at once) 150 gig
SATA - Media Courses storage (Movies flash etc for ICT iMedia) 50 gig
SATA - Common area (Used for all staff resources, mostly office docs and some movie clips etc) 150 gig
SATA - Admin Storage (only for admins special apps and storage, hardly used) 100 gig
SAS - Virtual Machines
Above are suggestions, don't know the usage patterns or how much space the VMs take so hard to be more precise.
I'd use RAID6 as this keeps all disks active but still has two redundant drives so if one drops there is very little performance loss unless rebuilding. RAID5 if must you require a hot spare just to give a bit extra space.