> I would like to get a Promise IDE raid controller, either the 4 or 6 > channel version, haven't decided yet. I was going to put on it 4 - 80 > GB EIDE hard drives with 7200 rpm and 8MB cache each. I would use these > in a raid 0+1 or raid 1+0 configuration. It is my understanding that > this will give me the best of both mirroring for redundancy, and > parity/spanning for performance. > > If I am right in my understanding of raid levels 4 - 80GB drives in such > a configuration will give me 160GB of storage space, with the other > 160GB of the drives being used in a mirrored capacity right? > > Opinions? Comments?
A RAID-5 would give you about the same security, but give you an additional 80 GB of storage. Only advantage of 1+0 with four disks is that it will survive a chrash of two disks, IF they are the right two disks. It could just as well die, if the two disks are on different mirrors. Something you should consider anyway is having a connected spare disk, which is used as a failover when a disk fails (again, if the RAID-controller permits it). That way the second disk would have to fail within an hour for the array to fail, instead of within the next time you go to work. RAID-5 would free up that disk, perhaps making it probably a more secure way of using four disks. The problem is, of course, that your raid controller might not support it. And the differences aren't that great (as you can see), so it's not really worth spending money on (however, if the RAID controllers are much more expensive than plain controllers, and you have a decent CPU, go for software RAID instead and save some money). I guess the best and easiest way is what you suggested (less setup etc.). But those are some alternatives. > I am leaning with EIDE solution because of price vis a vis scsi and > because sata really isn't available in my area yet and is still fairly > expensive/unsupported? Sata isn't much more expensive than IDE where I live (Norway). However it is mostly the interface that is different, the disks are the same and so it doesn't really matter (as long as you keep those IDEs on different channels!) BTW, my own setup is SATA-disks in software RAID 5 on Promise TX-controllers (non-RAID), works great (though that is a dual Xeon, don't know how it would perform on lesser servers). // Dag Sverre ------------------------------------------------------- SF email is sponsored by - The IT Product Guide Read honest & candid reviews on hundreds of IT Products from real users. Discover which products truly live up to the hype. Start reading now. http://productguide.itmanagersjournal.com/ _____________________________________________________________________ Ltsp-discuss mailing list. To un-subscribe, or change prefs, goto: https://lists.sourceforge.net/lists/listinfo/ltsp-discuss For additional LTSP help, try #ltsp channel on irc.freenode.net
