IBM Storage Solution 1

[Stevieboy]

Hi all.Can anyone advise me on this?We have two servers,a Dell Poweredge and an IBM Netfinity x series 250.Both are runnning NT Server and SQL Server 7.The Dell holds the live database.We need a device to sit between the two servers so that the database can be written to the device from the Dell and accessed by the IBM.The device needs to be seen as local to both machines-not networked as a network device is too slow.We also need random access to the device-not sequential and it needs to be FAST!! I believe what we need is called a differential drive but i may be wrong.Eventually the idea is to take the Dell offline completely as it is getting old but before we do we need the two servers running side by side for a while.Can anyone offer any ideas please ?Oh i forgot to mention the differential drive needs to be about 60-80 GB capacity...

Many thanks

Steve

 

[bjverzal]

A Differential Drive - you probably mean Differential-SCSI. Actually, nope - that won't help you. There are file-locking issues here. You can't have different servers physically connected to the same hardware and expect the data to be held consistently. If your main server has the database locked, the other server won't care and will attempt to read the data. This will cause bad results to come back to the other server. Sharing SCSI devices in this configuration will be a bad idea. Very bad.

Perhaps what you are looking for would be a NAS or SAN. Networked Attached Storage or Storage Area Network. Nope - they're not slow. When connected via Gigabit Ethernet (as ours is), the speeds are extremely fast. I' am seeing 33MB/sec across our Gb Ethernet segment - sustained. Theoretically, you can push roughly 134MB/sec across a Gb Ethernet segment, but I doubt you actually will.

SAN devices are designed to do exactly what you want to do - share large amounts of storage across multiple servers, but beware however of the file locking issues I mentioned. Be sure the IBM server is using the Dell Server's SQL Server connections, or else you'll have a high potential for data corruption.

Good Luck!

Bill.

 

[Stevieboy]

Thank you for your help.Much appreciated.

 

[Cr4igy]

The fastest you'll ever see out of a gigE link is about 95MB/sec pretty much irrespective of anything else.

Over 2GBit Fibrechannel you may get over 160MB/sec though.

Craigy