Does A8N-SLI Deluxe have Raid 5 online expansion?
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From: idon.wong on 21 Nov 2005 20:30 Hi all, I'm considering getting the A8N-SLI Deluxe mobo with a dual core Athlon 64 X2. I've read some articles which indicate the onboard Raid 5 performance is somewhat lacking, but i'd like to try it out anyways before investing in a dedicated Raid5 card. Anyways, my question is, does anyone know if the board supports online expansion? I mean, if i build a parity array with 3 drives, can i add additional capacity later by adding another drive and rebuilding the array, without losing the existing data? I've read that this is a feature most dedicated raid cards have. Thanks, iDon
From: Paul on 22 Nov 2005 04:04 In article <1132623041.239042.122080(a)g43g2000cwa.googlegroups.com>, idon.wong(a)gmail.com wrote: > Hi all, > I'm considering getting the A8N-SLI Deluxe mobo with a dual core Athlon > 64 X2. I've read some articles which indicate the onboard Raid 5 > performance is somewhat lacking, but i'd like to try it out anyways > before investing in a dedicated Raid5 card. > > Anyways, my question is, does anyone know if the board supports online > expansion? I mean, if i build a parity array with 3 drives, can i add > additional capacity later by adding another drive and rebuilding the > array, without losing the existing data? I've read that this is a > feature most dedicated raid cards have. > > Thanks, > iDon A real RAID card would get you an XOR engine (the chip with the heatsink) and a cache DIMM. Real RAID cards support in-place migration, so you can grow an array. These are not features you would expect from some $5 chip slapped on a motherboard. If you want speed and reliability, do a RAID 0+1 with four disks. You buy four disks, and get two disks capacity wise, which is worse economics, but the speed of the striped pairs more than makes up for it. It basically consists of two striped pairs, mirrored against one another. If you plan on using a RAID, I would also recommend the purchase of a UPS, so that the computer can go through an orderly shutdown during a power failure. Some UPSes have an interface, to signal to the computer, and the UPS software installed on the computer, can then shut the computer down when you are not present. That will help keep the two mirrored arrays synchronized, in the case of a 0+1. Also, if you want to play with RAID5, there was a recipe on Tomshardware, that would allow you to use vanilla drive interfaces to build a RAID. The speed of the RAID5 built this way, will emulate the performance to be expected from the A8N-SLI, so you can test the concept now, if you have enough disks. http://www.tomshardware.com/storage/20041119/index.html Paul
From: Leif Nordmand Andersen on 22 Nov 2005 07:58 Hi, >Also, if you want to play with RAID5, there was a recipe on >Tomshardware, that would allow you to use vanilla drive interfaces >to build a RAID. The speed of the RAID5 built this way, will >emulate the performance to be expected from the A8N-SLI, so >you can test the concept now, if you have enough disks. > >http://www.tomshardware.com/storage/20041119/index.html I'm actually using this 'hack' to run a 6x250 Raid 5 Configuration (1,13TB). I've not measured the speed, but it is used as a fileserver, and my 'feel' is, that it runs about 40% of the speed of a single SATA drive. However the way Toms describe the hack of the files DOES NOT WORK any more, if you have a fully updated Windows XP SP2, one of the files (can't remember which one) is no longe ASCII but Binary - so you can't find the string to change. However there are people out there who have hacked the binary file and changed the string - I use these files for my raid. Works without any problem Regards Leif.
From: idon.wong on 22 Nov 2005 19:22 Thanks guys. My plan is to build a new machine to act as my home office server which would operate 24/7. Since it is going to be on all the time anyways, i figured i might as well make it my network file server too, rather than buy a seperate NFS like Buffalo's solution. Since it'd mostly be hosting media content (like photos, movies, music), for read operations, i thought the Raid 5 CPU hit might be ok (plus i'd have a dual core CPU). I'd have another set of drives (possibly mirrored) for the other applications to run (and write) off of. That raises another question - am I able to enable both raid controllers at the same time? Anyways, here are the specs I've got planned. Any thoughts? AMD Athlon 64 X2 3800+ Asus A8N-SLI Deluxe OCZ PC3200 DDR400 Premier Series 1 Gb Dual Channel Asus GeForce 6200 128MB PCI-E Antec SLK3800B Mid Tower w 400W PSU 4x Western Digital SATA 320GB drives 2x Seagate ATA 200Gb (I have kicking around) DVD+/-RW drive My original question was aimed at whether i can save a few bucks now, not buy 1/4 320 Gb drives now, and add it later. Does the XP hack support expansion? Thanks, iDon
From: Paul on 22 Nov 2005 22:30
In article <1132705347.003366.15840(a)g44g2000cwa.googlegroups.com>, idon.wong(a)gmail.com wrote: > Thanks guys. > > My plan is to build a new machine to act as my home office server which > would operate 24/7. Since it is going to be on all the time anyways, i > figured i might as well make it my network file server too, rather than > buy a seperate NFS like Buffalo's solution. Since it'd mostly be > hosting media content (like photos, movies, music), for read > operations, i thought the Raid 5 CPU hit might be ok (plus i'd have a > dual core CPU). I'd have another set of drives (possibly mirrored) for > the other applications to run (and write) off of. That raises another > question - am I able to enable both raid controllers at the same time? > > Anyways, here are the specs I've got planned. Any thoughts? > > AMD Athlon 64 X2 3800+ > Asus A8N-SLI Deluxe > OCZ PC3200 DDR400 Premier Series 1 Gb Dual Channel > Asus GeForce 6200 128MB PCI-E > Antec SLK3800B Mid Tower w 400W PSU > 4x Western Digital SATA 320GB drives > 2x Seagate ATA 200Gb (I have kicking around) > DVD+/-RW drive > > My original question was aimed at whether i can save a few bucks now, > not buy 1/4 320 Gb drives now, and add it later. Does the XP hack > support expansion? > > Thanks, > iDon I don't do RAID myself, as I only have desktop configs for computers, but some questions I'll ask anyway... 1) What is your backup strategy ? Any time you plan on buying a whack of disks, with a large total capacity, do you plan on using that capacity ? Can you predict how many years it will take to fill it ? Is there any point going with 320GB drives ? 2) If you have a backup strategy capable of dealing with the sum total of storage capacity you plan on the new machine, then in-place migration becomes a non-issue. Simply backup and restore. Your backup solution should be capable of backing up the whole array, in an overnight time period (say 8 hours, so you are not bumping into the backup the next day). If the backup method was sector-by-sector, no compression, and a disk managed 50MB/sec transfer speed, then in 8 hours you can transfer 1.44 Terabytes. That implies the backup solution itself doesn't have to be striped to work. File by file backup wouldn't be practical if your large array was full, but makes sense if the array is mostly empty (seek time is a killer on backups, as is softwqre compression). This is one reason you won't find any big drives in my house, because it would cost too much to back them up. Each computer gets a tiny drive, with a tiny backup requirement. An 80 GB drive, with a second 80GB drive as a cold backup device, is enough for me. No matter how a RAID is constructed, the disks are all connected to the same power supply, and are sitting in the same ATX metal box. A catastrophy, like a lightning blast, or a PSU failure that overvolts all the drives, will negate whatever redundancy is in the RAID array. That means, even if you bought a $600 RAID card, added hot spares etc., your array could still be destroyed in a millisecond. Tape is too expensive to make a decent backup method. Using disks is an alternative, but a proper rotation strategy would require more disk drives than you would be happy with. DVDs would probably be too slow in backup or restore, to meet an eight hour objective. I think your first engineering task, is figuring out how backups will work. Constructing the RAID array will seem trivial after that. Yes, you can run more than one array at a time on your board. Maybe a smaller array, with more emphasis on off-line storage of stale content, would make more sense. You could probably afford to buy smaller disks, and make your RAID a reality today. Say 4 x 80GB plus a single 320GB disk to do a backup. That should have a reasonable starting price. You might also benefit from an external drive tray mechanism, to make inserting the backup drive easier. There are devices that have a small shell to hold the drive, which is then inserted into a drive bay. A second solution is to pick up a cheap SATA controller card, with an ESATA external port connector. That will allow transfers that are not limited by the performance of the cable (as would be the case with a USB2 or Firewire 400 enclosure for an external drive). It means the external enclosure needs no bridge board - just a power supply plus the SATA drive. http://store.yahoo.com/cooldrives/saingrsisadr.html Paul |