SANs - Where to start?

NightShadow

NightShadow

NightShadow

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I am looking into SANs and really am not sure where to start. We are looking to implement a SAN which will cover 2 geographic locations for redundancy/DR and I have been looking at the HP LeftHand networks P4300 16TB kit which seems OK but there isn't much info about how it all works. It will be used to host initially 250 Exchange 2010 users (roughly 200GB) but will probably eventually host our file servers etc. Where can I really learn about SAN technologies?

Do SANs have much disk redundancy?
Do all SANs incorporate de-duplication?
Can the P4300 16TB kit be split as 1 unit at each site? What would the total available storagebe?

As you can see I have lots of questions and havn't really found anything useful on the web so am after any pointers on where to start and what's good etc.

TIA
 
Wow, a lot of replies to this, havn't managed to fully read through yet but thought I should at least reply and update with requirements.

Were looking at implementing several virtual servers, mainly mail and B2D based with a view to move file server storage onto them in the long term. The main requirement is to have the data replicated to a separate site so that if one site should go offline for whatever reason the other site can continue to access emails, files etc.

I'm not sure we actually need De-duplication now that I have looked at it further. Will check out some of the suggested kit in the meantime to see what else is out there.

Thanks again
 
JBod said:
Depending on your budget 3Par are about the best at SANs. Awesome management interfaces.

No one has asked a very important question though, are you sure its a SAN you need and not a NAS? They are two distinctly different things targeted for different storage needs.

Are you able to share your budget? As it will quickly determine what level you are aiming at - Shoestring (Supermicro+Opensolaris with ZFS) - Entry level (Dell/HP) - enterprise (Netapp/BlueArc/3Par) - bullet proof bank storage (EMC). What kind of disks? SATA? SAS? FCAL?

Its not worth touching a EMC unless you have about £1mil to spend as their lower tier products are utter utter rubbish.
Click to expand...

Pretty sure it's a SAN we are after, B2D in Backup Exec requires "direct attached" storage IIRC which we can't do with a NAS, also from looking around a SAN has a lot more built in redundancy which is essential due to the data being held on there. The budget will probably only allow for "entry level" solutions such as the HP LeftHand and Dell offerings. As for disks, whatever seems to offer the best bang for buck, SATA would probably be fine.
 
I have another question...

Do SANs need dedicated switches or would running them on their own VLAN be feasible? Seems HP are pushing the dedicated netowrk hardware but is this actually necessary considering you would be looking at the best part of £8k for 4 switches.
 
Hmm, these SANs are proving more and more expensive the further I look. I have been given a quote of £24,000 for 1 Dell Equallogic PS6000XV with 16 x 450GB 15k SAS drives and dual controllers, this is for just 1 site! Do I need dual controllers? Assuming I am going to settle for ~3TB storage for the time being using RAID10 and replicating to another site this would work out over £50k with additional network hardware! I can/will be getting the price down by getting a quote for SATA but it still seems expensive for what you get.
 
Hmmm, had a quote in for the HP P4300 in a similar configuration as the Dell kit with 16 x 450GB drives @ £15,000. Seems a contrast to earlier experiences as it's £9000 cheaper per unit than the Dell equiv.

Just working out capacities & drive redundancy:

If I configure the Dell or HP to use RAID50 I effectively lose 2 disks and can handle 1 disk failure on each side of the RAID5 mirror?

Total available storage space is 6.3TB or are there any overheads that I have to take off of this figure?
 
brainchylde - What do you find the SATA disks like speed wise and how reliable have the drives been, HPs enterprise SATA drives only seem to have a 1 year warranty, not sure on Dell.

I have already asked for quotes with cheaper disks aswell, still unsure of the RAID setup, would be intesting to see the real world difference in speeds between SATA and 10k SAS in various flavours of RAID. Part of me thinks that 16 1TB SATA in RAID10 would be good enough and still have plenty of storage available whereas if we go for the SAS drives it would probably be used in RAID50 to maximise storage available.
 
Thanks brainchylde, how did you go about contacting dell to find out about your IOPS etc? I have filled in a form on the Dell site but heard nothing back so far. Did you demo any of the kit and what sort of price did you pay per PS6000E box full of drives if you don't mind me asking?
 
Right...progress...

So I have looked at various incarnations of Dell/HP SANs and am leaning toards heavily towards the Dell PS4000E with 16 x 1TB SATA

I recently ran some performance counters on our Exchange server and found that they spiked to 600IOPS in places but for the most part was below this, the only exception being our B2D which sustained just over 1000IOPS for the duration. Our Dell man has stated that the PS4000E can handle up to 1000IOPS and said it should handle it fine but what is the general opinion on this? If we add any more load during the B2D of Exchange surely we will hit problems here!

Is it generally a bad idea to run B2D on the same SAN which is used for production data?

I was also looking at HPs P2000 G3 SAN as they have a dedicated iSCSI version coming soon. Any poinions on these? I have only had a demo of a much older P2000 unit which didn't even have the latest user interface loaded. Been put off of the HP/LH SANs due to the requirement for a Quorum machine and also having a dedicated machine for the management interface..
 
Thanks for the responses guys. Will be using the SAN in a RAID10 configuration for maximum performance from the SATA drives, means using 2 drives as online spares but that I don't mind. Supposedly it whould give us 6.1TB of RAW capacity according to Mr Dell. Still not 100% on putting the B2D on the SAN, might try it out and see how it goes though, what happens if it exceed the maximum IOPS on the SAN, do I end up with corrupted/failed backups?

I have an MSA50 here aswell so might just get some bigger disks for it and use that for B2D to be on the safe side. Looking at Snapshots, I believe they are not entirely useful for Exchange/DBs unless they can quiesce the DB and pause the writes to it whilst it's take and I don't think The Equallogic supports this.
 
We will be hosting our VMs on DAS with mirroring and hot spare drives so shouldn't affect our them too much. We currenty do B2D2T backups every night was looking at keeping it the same, maybe changing to weekly tape duplicates instead.
 
PR. said:
Doh, wish I'd seen this thread earlier!

Currently looking at getting a SAN as we want to use it for storing Data Protection Manager 2010 backups, probably going to need about 5TB to backup everything was looking at the Equallogic P4000 (the basic) as 90% of the data it's going to receive is coming through 800k/s broadband lines!

Very price concious and I'm still waiting for our reseller to give us a price, I'm betting it's going to be too expensive :(
Click to expand...

We are looking at 1TB SATA in RAID10 for 6TB storage and currently pricing is coming in around £17,000 +VAT per PS4000E, plus support on top of that.
 
The SAN is going to be used for multiple servers including file servers and Exchange and will be replicated between 2 geographic locations, hence not using DAS. If it was solely for Exchange 2010 I would go for DAS as DAGs are great and wold be all I need!
 
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