Id like to do a raid 5 array for my file server with sata. if you use a abit or asus board that has 2 sata ports and raid, can you add a 2 port non-raid sata controller card and use the onboard raid of the mobo to do raid 5?
no cause that would cost me a full drive, because i want to use 3 200GB drives and in raid 5 that would be 600Gb but in raid 0 i would need another drive and only have 400GB
No it wouldn't be 600GB in RAID 5. If all you're wanting is large volumes and no data integrity, just use a JBOD array. If you are wanting data integrity, you're going to require four 200GB drives to have 600GB of storage with a RAID 5 array. RAID 5 stores parity information on each drive, so you lose storage capacity.
no cause that would cost me a full drive, because i want to use 3 200GB drives and in raid 5 that would be 600Gb but in raid 0 i would need another drive and only have 400GB
But... You realize that since a raid-5 array has to make reads from the other disks in the array for the parity info between each write that nothing is sequential and that all writes sux "A" then correct? So your nifty SATA drives will basicaly write at the speed of a 10 year old ide drive.
Meaning SLllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllooooooooooooooooooooooooooowwwwwwww?
I mean if you don't care that your nifty sata drive is slow as molasses in the winter and that you need a REAL raid controller not the chincy built in crap on most MB's to get that Sllllllllllllllllllllllllllllllllllllloooooooooooooooooooowwwww speed to start with then hey...... go for it bud!
But three 200gb's in raid-5 gives ya 400 not 600gb anyway. Ones parity remember? Every write is duplicated so with three drives you lose the capacity of one.
So go ahead... Bite for one more and go raid-10 and get twenty times the write performance... H*ll your paying for sata speed you might as well actually get some speed anyway right? Or do you wanta have your write performance sux big time like the others mentioned?
Raid-5 suxs on writes without serious bucks on a real raid controller. One with a fast cpu and fast ram cache on board. Can't be helped. Its what makes raid-5 what it is dude. The cheapie way to redundancy. Save your nickles and dimes and get one more disk please...
Some guy in the forum here in the last 2 or 3 weeks posted a sh*tload of links. Your problem if your not careful is reading too much and 25 percent of the crap you read is just that.... crap. Remember you don't have to really know squat about a subject to be published in cyberspace so take the source into consideration when you read up on this stuff. Hard disk or controller manufacturers often have whitepages published describing raid in general and the differant versions and the pro's and cons's of each.
raid-1 is pure mirror of a single drive. You lose the space of one disk for each one mirrored. A good controller can actually get double the read speed by reading from both drives alternately but the write speed stays the same. Not all controllers do teh fancy double the read speed either.
raid-0. Striped. Usually much faster as it alternates reads/writes across all members of teh striped set. The bad side is if you lose any disk you flush the whole thing.
Raid-5. We talked about this above. It writes parity info so basicaly all writes happen twice but... before it can make the second write it has to read from teh other drives to figure out where the next write needs to go each time. It allows ya to lose any single drive but the bad side is a huge performance hit IF you use it for an application that has even moderately heavy writes.
raid-10, this is a combo of raid-0 disks that are mirrored in a second raid-1 array. So you still lose half the space but its the best c ombo of performance and safety.
I have been setting up big servers for longer then I care to remember and would be glad to help if you want help.
also remember most the onboard raid from SI, HPT or Promise are really ide controllers with neat software to do the striping. Almost none if any do raid-5. Thats "software" not hardware raid. A serious hardware raid card has BOTH a onboard cpu (usually risc based) to handle the striping and a ram cache also.
If your interested in a serious SATA raid controller you really need to look at 3ware or LSI.
3ware has been the defacto standard in in high end ide/sata raid for a long time. I wouldn't even consider a sata raid-5 solution that didn't include either a 3ware or LSI controller.
k here is my situation I have a samba file server with 1 200GB hd and a 3GB that i run the OS on. I would like to back it up just in case god forbid. Could I use a external drive to backup, or what would you guys recommend? also Im gonna add another 200GB for more storage cause my 200 is getting full.
And my questions about an external like a fireware or usb 2.0 drive would revolve around how well linux handles it. If it handles a external usb 2.0 then go for it. Another easy option though would be a removable ide drive bay. You can get realy fancy ones for 20 to 25 bucks or....
I have a mixed linux windows network at home but I run gigabit ethernet and back up critical data from one server to another server online. Everything everywhere sits at least on two seperate servers. You can hook up two gigabit cards directly without a switch even if you are gonna go cheap and back up two servers to each other. You can scarf a pair of nice gigabit cards off ebay for under 50 bucks. Better to get good used ones then cheap new ones. I bought some cheap new 32bit cards that didn't hadly transfer fastewr then 100mbit.
But moving to gigabit was one of the best moves I ever made at home. I got a nice 8 port smc gigabit switch that even supports jumbo frames for under 125 bucks or so.
You can probably get a 4 or 5 port for under 90 bucks.
also remember most the onboard raid from SI, HPT or Promise are really ide controllers with neat software to do the striping. Almost none if any do raid-5. Thats "software" not hardware raid. A serious hardware raid card has BOTH a onboard cpu (usually risc based) to handle the striping and a ram cache also.
If your interested in a serious SATA raid controller you really need to look at 3ware or LSI.
3ware has been the defacto standard in in high end ide/sata raid for a long time. I wouldn't even consider a sata raid-5 solution that didn't include either a 3ware or LSI controller.
3Ware has had some problems lately with data corruption. I originally found out about it at 2cpu.com but they just had a little snippet about it and then linked to another site (StorageReview perhaps?).
k here is my situation I have a samba file server with 1 200GB hd and a 3GB that i run the OS on. I would like to back it up just in case god forbid. Could I use a external drive to backup, or what would you guys recommend? also Im gonna add another 200GB for more storage cause my 200 is getting full.
I believe if you use ghost 2002 or 2003 with usb support loaded in (for 2002) you should be able to ghost an image of the 200gb drive to a USB2 drive.
Comments
Also, do you really need RAID 5? RAID 1 might better serve your needs and be much less costly.
But... You realize that since a raid-5 array has to make reads from the other disks in the array for the parity info between each write that nothing is sequential and that all writes sux "A" then correct? So your nifty SATA drives will basicaly write at the speed of a 10 year old ide drive.
Meaning SLllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllooooooooooooooooooooooooooowwwwwwww?
I mean if you don't care that your nifty sata drive is slow as molasses in the winter and that you need a REAL raid controller not the chincy built in crap on most MB's to get that Sllllllllllllllllllllllllllllllllllllloooooooooooooooooooowwwww speed to start with then hey...... go for it bud!
But three 200gb's in raid-5 gives ya 400 not 600gb anyway. Ones parity remember? Every write is duplicated so with three drives you lose the capacity of one.
So go ahead... Bite for one more and go raid-10 and get twenty times the write performance... H*ll your paying for sata speed you might as well actually get some speed anyway right? Or do you wanta have your write performance sux big time like the others mentioned?
Raid-5 suxs on writes without serious bucks on a real raid controller. One with a fast cpu and fast ram cache on board. Can't be helped. Its what makes raid-5 what it is dude. The cheapie way to redundancy. Save your nickles and dimes and get one more disk please...
tex
Nobody benches more HD Raid configs than he does....
raid-1 is pure mirror of a single drive. You lose the space of one disk for each one mirrored. A good controller can actually get double the read speed by reading from both drives alternately but the write speed stays the same. Not all controllers do teh fancy double the read speed either.
raid-0. Striped. Usually much faster as it alternates reads/writes across all members of teh striped set. The bad side is if you lose any disk you flush the whole thing.
Raid-5. We talked about this above. It writes parity info so basicaly all writes happen twice but... before it can make the second write it has to read from teh other drives to figure out where the next write needs to go each time. It allows ya to lose any single drive but the bad side is a huge performance hit IF you use it for an application that has even moderately heavy writes.
raid-10, this is a combo of raid-0 disks that are mirrored in a second raid-1 array. So you still lose half the space but its the best c ombo of performance and safety.
I have been setting up big servers for longer then I care to remember and would be glad to help if you want help.
tex
If your interested in a serious SATA raid controller you really need to look at 3ware or LSI.
3ware has been the defacto standard in in high end ide/sata raid for a long time. I wouldn't even consider a sata raid-5 solution that didn't include either a 3ware or LSI controller.
I have a mixed linux windows network at home but I run gigabit ethernet and back up critical data from one server to another server online. Everything everywhere sits at least on two seperate servers. You can hook up two gigabit cards directly without a switch even if you are gonna go cheap and back up two servers to each other. You can scarf a pair of nice gigabit cards off ebay for under 50 bucks. Better to get good used ones then cheap new ones. I bought some cheap new 32bit cards that didn't hadly transfer fastewr then 100mbit.
But moving to gigabit was one of the best moves I ever made at home. I got a nice 8 port smc gigabit switch that even supports jumbo frames for under 125 bucks or so.
You can probably get a 4 or 5 port for under 90 bucks.
tex
I agree 100%
3ware rules
// Edit: Found it: http://forums.storagereview.net/index.php?showtopic=14162