Re: Raid 5 build (Beginners)
What exactly is it for? Why does he want RAID5?
Basically, depending on answers, you are looking at one of the following:
1. a NAS solution
2. a HP Microserver
3. A machine where half his budget is just for the RAID controller...
Re: Raid 5 build (Beginners)
A fileserver for his business - we need a motherboard that has hardware raid mainly but i read somewhere that all modern intel southbridges support raid 5 for sata 2 drives.
http://www.scan.co.uk/products/gigab...ga-on-board-at
Would tht work?
(Note we specifically want Raid 5 hardware motherboard for a server - not just a NAS drive etc)
Re: Raid 5 build (Beginners)
Quote:
Originally Posted by
richieuk
A fileserver for his business - we need a motherboard that has hardware raid mainly but i read somewhere that all modern intel southbridges support raid 5 for sata 2 drives.
http://www.scan.co.uk/products/gigab...ga-on-board-at
Would tht work?
(Note we specifically want Raid 5 hardware motherboard for a server - not just a NAS drive etc)
http://www.gigabyte.eu/products/prod...px?pid=3884#sp
Re: Raid 5 build (Beginners)
Yes, it will work. Performance will not be very good though and if the mobo dies (or even if the BIOS needs updating) the raidset can get broken and will need to be restored from backup (RAID is resilience, it is in no way a replacement for backup!!!!!!!!!!!!!!!!!!!!!!!!!!!! <- I cannot stress that enough!!!!!!!!!!!!!!!!!!)
If he just wants to share files (i.e. doesn't want to load a domain controller, mail server, SQL server etc) then I would seriously look at a NAS solution, ideally one with good support as it's for a business.....or a HP Microserver.
Re: Raid 5 build (Beginners)
Intel mother boards (intel raid matrix) is not a hardware raid, it uses the drivers to do this. Why is this bad? If you have N disks in the raid you need to do N-1(+<1) reads and 2 writes for every write operation. This works the IO controller hard, so for safety writes are synced to disk, this gives poor performance. Hardware raids are better for 2 reasons, first you do one write operation to the controller, it then does the necessary reads and write, and secondly it uses a cache for the writes, this cache has battery backup so if the power fails mid write, it will synchronise the disks after the system reboots. Another thing to consider is how easy is it to remove a failed disk from the raid array and add a new one. When using the Intel system on a linux platform, I had disks drop to inconisant states, and was in general a nightmare. So now I use software raid (mirroring) you can also do a software raid with windows. However I really would get a proper raid card if it is for a real server or stick to mirroring drives. With 2TB and 3TB drives do you really need Raid 5 for a small setup. Mirroring (raid 1) is much fast, and does not require multiple reads for maintaining a parity. Raid 5 also uses a stripe size (normally 32K) This means any write to this area, will required not just the few bytes read, but the complete stripe must be read from all drives. the cache again solves this, as it delays the write as data is often sequencal, meaning the data after that point rather than being read, will also need to be written to the disk.
Re: Raid 5 build (Beginners)
Re: Raid 5 build (Beginners)
Sorry - Shows how nooby I am, I'm going off second hand information from my friend :P
Right lets start again - He was quoted for a "Micron and Intel Motherboard ICH8 Raid 5 Hardware Controller" and he wanted me to help him get a cheaper alternative (and more modern).
A bit of reading showed than the ICH8R was Raid 5 capable and I assumed that the raid was hardware raid on chip. I went on to read that ICH10 southbridges were also Raid capable and assumed that the gigabyte board I mentioned would suffice.
What I ACTUALLY need is a cheap but decent hardware raid 5 solution, preferably Raid-on-chip hardware, but we will consider a standalone PCI-Express controller if its cheap enough. The specifics are limited to Raid 5 Hardware controller and Intel chipset (preferablly i5 capable) so any help would be really great
Application is not in question here btw ^_^
Re: Raid 5 build (Beginners)
You're looking at something like a PERC5/i or similar (maybe a HP E200?), complete with battery backed writeback cache - performance should be ok at that but nothing too stellar for RAID5 (as mentioned by Oolon, it's not the fastest for a number of reasons). Then you're looking at a spare controller and BBWC for when the first one fails (if it's for business you really don't want to be waiting for a replacement to be delivered if you have important business data in there, do you?). There goes a pretty fair chunk of your budget before you even look at other aspects of the system, not least of which will be the disks in question (do you need RAID grade disks? if so they'll soon add up too)
Those ICH8 controllers are not hardware RAID, no matter what the salesman tells you.
