On Friday 01 June 2007 11:46, Phillip Bennett wrote: > > I am looking at replacing one of my Linux servers here at the moment and > wanted to ask people about their experiences with hardware configuration.. > > Basically, it will have about a terrabyte or so of space available in the > form of a RAID array, (probably RAID5)
Phillip - you've got this kind of backwards. A mopre sensible way round would be to start with the application, then price, then start thinking about physical arrangements and RAID levels. > and I was wondering if anyone would > be able to tell me the pros/cons of having all this available in just ONE > array, as opposed to having two or more smaller arrays. It really rather depends how you split the arrays; we don't know if RAID 5 is the right way to go for your data. Assuming it is, then it's so small it'd be difficult to do it in anything other than a single 'big' array. Depending on your budget you may want to eliminate the controller as a single point of failure - you probably don't want to put more than about 4 disks per channel anyway for bandwidth purposes. > Are there > performance advantages that people know about? I realiase that with two > smaller arrays, there is less risk to data, but more cost for disks, but > could this be offset by buying larger (750G) drives? ? this is nonsensical. Sure, if you layer say mirroring on top of striping, raid 5 on top of mirroring, you can get large volumes with higher reliability, but for a 1Tb array? The more disks you split your data over, the more reliable it should be but it doesn't follow it will be faster - bigger disks tend to be newer and faster. > For those wondering, it'll be a PowerEdge 2950 with all disks internal, as > opposed to an external array. Will this make a difference? Currently there's not much to choose between SATA and SCSI for streaming reads but random reads / writes are still (IMHO) handled better by the latter. OTOH there's a huge price difference. If you're wanting something substantial to go on, then, if its a fileserver, probably 5 250Gb SATA drives is the sensible way to go RAID5 across 4 of the disks with one as a hot standby. For a relational, transactional database, then RAID 1 (software) on top of RAID 0 (software or hardware) with SCSI disks is probably the sensible way to go. I've just had a Google - the 2950 is kind of small (2U) - and you want all the disks internal???? Putting the disks internally is the only design constraint you've given - but it is a big problem! Try to rethink this if you can. C. _______________________________________________ Scottish mailing list [email protected] https://mailman.lug.org.uk/mailman/listinfo/scottish
