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having a mirrored HD would be the Ideal situation, you get 2 HDs of equal size (the mirror can be bigger) make sure they are both dynamic disks and then you can mirror the drives through Disk management

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having a mirrored HD would be the Ideal situation, you get 2 HDs of equal size (the mirror can be bigger) make sure they are both dynamic disks and then you can mirror the drives through Disk management

Could i buy a Hitachi SATA to do this? How do i know if theyre dynamic disks?

If i use Disk Management to do the mirroring is it straight forward or is there a tutorial i can follow?

thanks

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A mirrored hard drive wont prevent any of the following:

Virus Infection

Data Corruption

Accidental Deletion

Theft

Fire

Flood

Power Surge

Mirroring is good in the event of HD failure as an addition to your normal backup routine, not as a replacement. I use a combination of Ghost, DVD burner and a network drive which I copy files to.

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Yes i only want to have it incase one hard drive goes down. We have backups but just want to ensure if one drive does go down we can use the other one until the original gets replaced. Should i therefore buy an exact same type of hard drive that i currently use? or a cheaper version of it but with the same space?

Thanks

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for the sake of consitancy i would stick with the same drive type/model if possible, technically you can use any 2 drive of the same size or greater for a mirror, i have heard of some problems when you mix drives from different vendors and speeds, i would go after the same drive you have just to be on the safe side

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Yes i only want to have it incase one hard drive goes down. We have backups but just want to ensure if one drive does go down we can use the other one until the original gets replaced. Should i therefore buy an exact same type of hard drive that i currently use? or a cheaper version of it but with the same space?

Thanks

Are you talking about a home computer or a company file server? If it's a file server in high demand then RAID 1 will degrade performance. I use 3 HDs in RAID 5 on the main file server at work.

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for the sake of consitancy i would stick with the same drive type/model if possible, technically you can use any 2 drive of the same size or greater for a mirror, i have heard of some problems when you mix drives from different vendors and speeds, i would go after the same drive you have just to be on the safe side
Ok - would this degrade performance? as its a 300GB har drive
Are you talking about a home computer or a company file server? If it's a file server in high demand then RAID 1 will degrade performance. I use 3 HDs in RAID 5 on the main file server at work.

Its at work (may try it at home if i succeed :thumbup ) Its just got files on there. Not high in demand but we have about 20 people who can use it at any one time. I was checking the definitions of RAID at http://linux.cudeso.be/raid.php#raid5 - I think im looking for something with decent performance to mirror but your telling me RAID 1 will degrade performance so which one is suitable?

Cheers

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I think im looking for something with decent performance to mirror but your telling me RAID 1 will degrade performance so which one is suitable?

RAID 1 is the slowest RAID because the server has to read/write to two drives at the same time, which doubles the work load. If you access a 1Mb file in a two drive RAID 1 set up, the server will access the same file from both drives, meaning 2Mb will be read in total (in case a drive dies during the process).

In a RAID 0 set up with two drives, if you open the same 1Mb file, 512Kb will be read from one drive and the other 512Kb will be read from the other. although this system is very high in performance, all data will be lost if just one drive fails.

If you've only got 20 people though, you don't really have to worry about the performance hit as I doubt anyone would notice. Especially with a fast 300Gb drive. It depends really, if all 20 people access large PST files stored on the server using Outlook at the same time then there would probably be a slowdown. Or if you're running 2003 server and your making regular shadow copy's while everyone has a lot of files open then they might notice a slowdown.

Anyway, to answer your question, RAID 5 would be a good choice. RAID 5 is a bit like RAID 0 except it uses an extra drive for parity. To clarify, if you access your 1Mb file, 512Kb will be read from one and 512Kb from the other - just like RAID 0. This is very fast. If you save a 1Mb file however, it will be written in strips across across the drives with the parity bits. These extra parity bits impact performance meaning it will write faster than RAID 1 but slower than RAID 0.

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Sorry but RAID5 is slower than RAID1. Calculating the parity information adds to the time it takes to write files to a RAID5 array. RAID1 writes are a simple write to both drives and then check to see if they match. With RAID5 the controller has to figure out how to stripe the files, calculate the parity information, write it all, then check to see if it all wrote correctly. Don't get me wrong, a good hardware based RAID controller can make this happen VERY fast, but RAID1 will still be faster.

There's also the additional overhead of cost associated with RAID5. Not only do you have to have at least three drives, but you also have to have a controller that supports it. A good controller that supports hardware RAID5 will set you back some bucks.

Since the size of drives have increased, I've moved to RAID10 (two or more RAID1 arrays striped) on my newer servers. The difference is noticeable, and I potentially have better redundancy (one drive from each sub-RAID1 array can fail and it's still operational).

Also, don't use Disk Management to do the mirroring. That's software based RAID and will be slower. Software based RAID will increase your CPU utilization on the server. It'll work in a pinch, but you should be looking towards a harwdware based option.

As for the drives, you should always use matching drives in a RAID setup. It's not necessary, but highly recommended.

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