Newbie SAN Questions 1

[gmail2]

Hi all

I'm new to the world of SAN's and need some help deciding what route is best. Can somebody help me out with the following questions?

1. Is it possible to put a SAN at our HO and one at our DR site and have their synchronize over our existing WAN link (using iSCSI or fcip?) ? Do we need any additional 3rd party software for this and if so can anybody recommend any ? How would I handle failover to the DR site incase the server at the HO failed but the SAN was still operational ? Should I just use DFS-R instead for this ? Or would Windows clustering work ? I've never dealt with Windows clustering so I don't know too much about it unfortunately.

2. If no 1 is possible, is it also possible to only synchronize data on certain array's ? Eg synchronize Array A to DR site but don't synchronize Array B?

3. If I have a SAN "feeding" space to 3 different servers, is it possible (again, using 3rd party software if necessary) to dynamically re-assign spare space from one array to be used by another server ? As I understand it, with "native" SAN setup an entire array must be assigned to one server ?

OK sorry ... slightly more than 3 questions there ! But hopefully somebody can point me in the right directions. I've tried googling some of this stuff but it's not giving me the exact answers I'm looking for

Thanks again !

Irish Poetry - Karen O'Connor
Irish Poetry and Short Stories - Doghouse Books
Garten und Landschaftsbau

 

[chgwhat]

Hi gmail2

First most SAN's present luns to host as disks, luns are a piece of an array. All SAN's I have worked with synchronize data at the lun level. To synchronize data with a remote site, the SAN or Switches need to support IP normally FCIP, and usually it is added cost for a SAN ie. remote mirror. If host fails at HO, you will have to advise the san the DR is primary and HO is secondary so it synchronizes the other way, and then start your hosts at DR site. You cannot write to both sites.

Tony ... aka chgwhat

When in doubt,,, Power out...

 

[gmail2]

Thanks for the reply chgwhat. Just one questoin - I thought a LUN was an entire array ? How do I present a LUN to a server as part of an array ?

Regarding the HO and DR sites, understood. That helps my research somewhat

One final question - have you ever heard of or looked at HP's Scalable NAS ? Althought it's called a NAS it appears to be a SAN (from what I can see !)

http://www.compaq.com/storage/software/clusteredfs/index.html

Irish Poetry - Karen O'Connor
Irish Poetry and Short Stories - Doghouse Books
Garten und Landschaftsbau

 

[gmail2]

ooh ... one other question, which you'll probably hate me for asking ! iSCSI or FC ... would you choose one over the other ? Or when is one better than the other

Irish Poetry - Karen O'Connor
Irish Poetry and Short Stories - Doghouse Books
Garten und Landschaftsbau

 

[denisfr]

Hello,

a LUN is the smallest part (usually an aggregate of cylinders taken among physical disks of your array) that can be made visible to a host by the way of a 'unmasking' command on your array.

For data replication, you can also consider high performances arrays that can be synchronized by the way of a specific link between them (optical fiber...).

And the difference between iSCSI and FC can be the price, mostly.

 

[chgwhat]

Hi
HP's Scalable NAS is a NAS gateway, there are a lot of them out there, generally an appliance you put in front of a SAN to serve file shares / NFS. iSCSI and FC is price and performance and depend on your requirements, and infrastructure.

http://searchstorage.techtarget.com/news/column/0,294698,sid5_gci1161824,00.html

Tony ... aka chgwhat

When in doubt,,, Power out...

 

[bilbus]

1. Yes, you can syn data between SANS and we do that on our DR site (not something i do) But i know it's done. We can lose a dataceneter and still have up to date data. Keep in mind, thats alot of data .. so you will need the bandwidth to do replication. We have 2 OC192's between our 2 DC (2x10G Ethernet) So replication and vmotion between datacenters is very fast.

3. I am not sure, some sans allow for thin previsioning if that helps.

As far as i know, you asign a lun, its for that server.