SAN information

deadfingers

Hi,

I work in a small company, we currently have a web server that 50% of the network traffic is internal, so I am currently purchasing a second server, one for all internal users and another for all external users. This we hope will improve performance for all users but while I was specing out a server from Dell I noticed a section on storage. I then started to look at a small simple SAN system. I am finding it hard to get my head around the whole idea of a SAN. My current thinking is that if I purchase the SAN (Raid controller) will I be able to share the data between both servers and each server will be able to pull information from the SAN. So inessence the SAN in its simplest form is an external hard drive that can be shared between servers? And can I directly connect a tape drive to a SAN to do the backups?I feel I am be totally of the mark or even going into too much complexity for the task? I have read a number of tutorials and its still a bit shady so any help or suggestions will be a great help.

seamus

(it NAS, not SAN )

I've never tinkered with NAS's, but to the best of my knowledge they are essentially dumb file servers with varying degree of manageability and integration for existing networks.

At a base level, any decent NAS should allow for Kerberos/LDAP/Active Directory integration for share security, and at least provide an external RAID or USB connector for your backup solution.

As I say, I've not tinkered with them, but I can't see any reason why they couldn't be used as auxiliary storage for servers - perhaps even mounted as a drive, or as a fully-fledged file server for user access.

deadfingers

Thanks Seamus,

No it is SAN, although there is a NAS and I am not sure of the difference. Do you feel it would be to much work to set it up? Would it provided reduency in our network?

Kali

There is a difference between a SAN and a NAS..

The former typically takes up at least one rack containing several disk arrays, at least one array controller and fibre switches for host connectivity... very costly and difficult to implement but very quick and has a lot of integrated failover and redundancy.

A NAS, unlike a SAN, transfers data over an existing TCP/IP network (using SMB/CIFS), typically a NAS unit is 2/3u containing anywhere from 4 to 8 disks... because it uses the existing network its typically pretty slow.. and more appropriate for backups, archives etc. than frequently accessed files (mail/databases etc.)

There is one other option which sits somewhere between the above two in terms of cost and speed, and thats fibre/scsi attached storage.. basically a 2u/3u box containing 6/8 disks and is typically directly attached to one or two hosts (via scsi/fibre).

Dell/HP sell all of the above solutions... find out what you need first and then implement it... i.e. is it a database backend that needs to be accessed? Why not have a seperate database machine so with the two webservers accessing it seperately? Find out where the performance issues are arising first and see to that... adding storage won't help.

seamus

deadfingers wrote:

Thanks Seamus,

No it is SAN, although there is a NAS and I am not sure of the difference. Do you feel it would be to much work to set it up? Would it provided reduency in our network?

I do apologise. Storage Attached Networking -v- Network Attached Storage. Absolutely no idea what the difference is (if there is one).

I'm not sure about them providing redundancy in the network. The very main benefit is that you get to add a new file server, or high-performance disk storage to your network at a much cheaper price than building a brand new server with equivalent storage, or managing a major upgrade to an existing file server.

[Edit: Kali proves me completely wrong ]

deadfingers

The current server is a database backend and due to the age of the server and expansion of databases the server is just not fit for the workload. So if i purchase the new server and the Dell 2u/3u boxs I can allow both the internal webserver and external webserver access the information on the 2U/3u box and in the future if the data increases again I can added another disk to the 2u/3u box rather than having to upgrad/purchase a new server?

po0k

seamus wrote:

I do apologise. Storage Attached Networking -v- Network Attached Storage. Absolutely no idea what the difference is (if there is one).

I'm not sure about them providing redundancy in the network. The very main benefit is that you get to add a new file server, or high-performance disk storage to your network at a much cheaper price than building a brand new server with equivalent storage, or managing a major upgrade to an existing file server.

[Edit: Kali proves me completely wrong ]

SAN == Big box
NAS == Little box

Kali

Quite honestly it sounds like you just need a new machine with a bit of space to host the database on... and leave the webserver as is.

If future space issues and upgrades are an issue I'd reccomend either going for a HP DL380 G4, Dell Poweredge 2850 or a Fujitsu RX300 (presuming you do have a rack to put them into)... these offer space for upto 6 HDs in various raid configurations, dual processors, upto 16GB RAM, redundant power supplies, remote management etc. etc... i.e. the perfect servers for future upgrade possibilities.

As I said above it sounds like storage alone won't solve your performance issues.. so at least the above gives you a brand new machine and a bit of space (if configured properly)... if you need contact details to get a quote on the HP gear give me a PM (I'd easily reccomend Redstone).