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Boot from SAN - pros and cons

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Albatross
Regular Advisor

Boot from SAN - pros and cons

Hi Folks,

Please, may you help us? We are discussing this topic with a costumer, mostly addressing availability concerns.

We understand the recommendation of not booting from a busy (high IO) SAN device.

The environment is based on BL460c and EVA4400, running Win2008 x64.

My take is that we can improve performance booting from mirrored local disks, with a BBWC. These disks will have the swap file, and data will reside on the EVA.

Any comments and insight will be gratly appreciated,

Thanks in advence,

Albatross
4 REPLIES
IBaltay
Honored Contributor

Re: Boot from SAN - pros and cons

Steven Clementi
Honored Contributor
Solution

Re: Boot from SAN - pros and cons

BfS is not for everyone. Basically, it is a decision that needs to be made based on the customers disaster recovery plan.

Just like you have to answer.. How much reduncancy do we really need?

You need to figure out.. How much dr do we really need?

BfS provides specific dr capabilities. Replicated Operating Systems could be one. The need to not have to rebuild your OS totally from scratch allowing for faster recovery.

How about the ability to deploy a new server with just the click of a mouse to built the os? Some disk arrays allow for making Clones of logical/virtual disks. If you created a "template" os and made a master clone... you could than make clones of it to deploy additional servers.

Typically, having your OS on a different scsi bus (whether scsi, iscsi, fc, etc) is usually better for performance and sometimes required as per OS specifications.

With Win2008x64, you might not notice much difference.

The real question to ask is... what is the server going to be utilized for?

If you are only considering BfS for one particular server and are NOT migrating to BfS or redesigning for bfS... then it probably makers more sense to use local disks.


Steven
Steven Clementi
HP Master ASE, Storage and Clustering
MCSE (NT 4.0, W2K, W2K3)
VCP (ESX2, Vi3, vSphere4, vSphere5)
RHCE
NPP3 (Nutanix Platform Professional)
S. Boetticher
Regular Advisor

Re: Boot from SAN - pros and cons

our experience: all of our SAN attached servers (around 25) do BfS (win2003, 2008) since we started with EVA3000 (now 2 EVA4000 with CA). We never had an issue, and I can really recommend it, because you get a lot of benefits:
you can use Snaps, Clones, CA for keeping valid states before updates, having a working OS copy in the background (if your windows will be not working as before) and to survive a loss of the primary EVA (and the server room) if you have comparable hardware in 2nd server room with 2nd EVA (we have test/dev-servers in 2nd room, so if we loose primary server room we stop test-servers and boot the primary systems from CA-mirror on comparable (does not need to be identical!) hardware...

BUT: we followed the rules/recommendations about not putting windows pagefiles on SAN to not risk BSOD in case of overloaded SAN. So each server got a RAID1 local storage for pagefile (so if we have to switch to other "site" we just have to adjust pagefile settings and reboot again).

Also you could clone OS and apply new SIDs to save time on deployment (we didn't do because we seldom get new real SAN servers).
Marcus Schack
Trusted Contributor

Re: Boot from SAN - pros and cons

And here is something from HP side of the house.

http://h18006.www1.hp.com/storage/networking/bootsan.html