Implementing a SAN

[u8dmtm]

We have decided to implement a SAN. Has anyone recently done this, and if so, what advice can you offer?

[bossman]

We are looking at doing the self same thing in august a 2.6Tb formatted solution with 5 brand new spanking servers running CC4 with a D2D2tape with 10Tb capacity.

So far we have 2 runners in the game and they are HP who offer blades with san backend all in one so you don't need a designated fibre switch and RM who are offering a similar solution with a fibre switch.

They both come in around the same cost so it is down to the service and care which both offer as to who we go with.

Also Dell do San solutions it might pay to get in touch with them.

 

Sorry can't give all the info as they have yet to get back to me for the second round of negotiations.

[torledo]

i would also advise you have a chat with dell.

 

They've recently bought equalogic, one of the leaders in iscsi arrays.........so they'd probly be able to quote for a complete iscsi san solution including support. Or you could source you're own gigabit ethernet switch and get the storage from dell.

 

Another iscsi option is storevault, the storevault can do NAS aswell in case you want to do both block and file or you get bored of iscsi.

 

The alternative to iscsi is fiber channel, which requires specific fc switches, or as boomam has said a dedicated fc blade within a blade center....

 

ontop of the cost of fc switch, sfp's, arrays, there's the cost of the fc hba's which are very expensive. So fc isn't the cheap option, even if you use a relatively cheap array such as an hp msa 10000.

[tmcd35]

We in the process of upgrading to a SAN here. We tried the ultra cheap option of a 'DAS' RAID box attached directly to two servers as local storage and now realise we need a bit more...

 

We're keeping our DAS box - A Promise unit with 12 SATA-II drives, 10 in RAID-50 and 2 hotspares 2.5Tb total, and connecting it to a purpose built server running SANMelody. Having played with the demo of the software I think this is fantastic way of building an iSCSI SAN.

 

The SAN is going to be on a separate IP range/VLAN to our main network with 1Gbps ethernet between all devices on the SAN. We're connecting two ESX servers and a Win2K3 box to the SAN (in addition to the SAN server).

 

One particularly nifty feature of SANMElody (I don't know if other SAN products offer this) is the idea of a storage pool and virtual volumes. On our test bed has two 250Gb hard drives in the pool. The pool has 4 virtual volumes allocated to it, sharing the 500Gb between them. Each volume (read LUN) identifies itself as a 2Tb drive with the OS it's attached to over the SAN. So we have 4 x 2Tb volumes sharing 500Gb of space. Obviously we can't use more than 500Gb as that's all the physical space we have. But if we do get to 80% full then SANMelody will notify and all we have to do is add an additional drive to the pool to increase the available space to all volumes!

Edited March 5, 2008 by tmcd35

[Geoff]

One particularly nifty feature of SANMElody (I don't know if other SAN products offer this) is the idea of a storage pool and virtual volumes. On our test bed has two 250Gb hard drives in the pool. The pool has 4 virtual volumes allocated to it, sharing the 500Gb between them. Each volume (read LUN) identifies itself as a 2Tb drive with the OS it's attached to over the SAN. So we have 4 x 2Tb volumes sharing 500Gb of space. Obviously we can't use more than 500Gb as that's all the physical space we have. But if we do get to 80% full then SANMelody will notify and all we have to do is add an additional drive to the pool to increase the available space to all volumes!

 

These are standard SAN features.

[markcuk]

we have been looking at the HP EVA4100 Starter Kit but have found fujitsu do a similar one alot cheaper.

[xenonive]

We currently have 2 x 6TB intel SANs , they are setup to mirror across CAT6 and i have positioned them either end of the school for fire protection. We are running 8 virtual servers on the SANS and the speed improvement is alot over raid 5. Any questions feel free to send me a message.

[spc-rocket]

We currently have 2 x 6TB intel SANs , they are setup to mirror across CAT6 and i have positioned them either end of the school for fire protection. We are running 8 virtual servers on the SANS and the speed improvement is alot over raid 5. Any questions feel free to send me a message.

 

Hiya,

 

Are you using this via iSCSI or Fibre channel?

 

Ash.

[tmcd35]

Ash,

 

I hate to point out the obvious, but... CAT6 would be iSCSI.

 

Terry.

[spc-rocket]

Ash,

 

I hate to point out the obvious, but... CAT6 would be iSCSI.

 

Terry.

 

Yeah i figured this after pressed the submit button! doh!

 

Ash.

[torledo]

These are standard SAN features.

 

What SANmelody and similar products should be able to do which is not a standard SAN feaure in the entry level is storage virtualization. This basically involves presenting physical disks from one or more storage arrays as single volumes to hosts servers, it abrstracts the physical layout of the disks on each array and it's greatest value is when used across more than one array, even if those arrays are from different vendors. This provides a single pane of management and makes the most efficient use of storage space. Is it of great value to one or two arrays, probably not....but if you've got lots of arrays from different vendors it can come in very handy, and actually saves money. TBH if you need storage virtualization you should have the dough for more advanced products e.g hds usp.

 

Storage virtualization isn't the only feature of SANmelody but it's the main reason people buy similar products such as ipstor. Both SANmelody and ipstor are software solutions, while ipstor sits inline between the hosts (ip) and the SAN fabric (iscsi or FC).....performance in both is an issue that's why there's a big jump price wise to the top two hardware virtualization products........HDS usp and IBM SVC.

 

to the poster considering the EVA4100, i'm not surprised you want to go with a cheaper array.....the EVA range is very expensive, if i had that kind of money i wouldn't be buying the EVA4000 range which is a bit long in the tooth. HP's best storage product is one they OEM from hds, much better going with something else for the entry or mid-level budget.

[xenonive]

Just to confirm it is iSCSI , due to the distance across the school the SANs are really connected by fibre cable via module in gigabit switch to another gigabit switch other end. To mirror intel SAN you require a ping time of <9ms ideally hence why have setup another gigabit LAN(192.168.0.*) just to keep the traffic on the SANs internal and then each server that is connected SAN via iSCSI is configured with a second LAN card with 192.168.0.* range. Hope the information helps.Ive been running for them about year and half now and have not had many problems but we did have about 20 powercuts in 3 months and things worked fine after but does sometimes takes up to hour for SANs to resync.