General discussion


Disk size for software RAID-5 setup?

By netforce ·
I'm setting up Server 2003 for dynamic disk and tooling around with mirror/spanned volumes/raid-5 etc.

Heres the thing I know you need at least 3 physical drives for software RAID-5.
I just purchased a new 80gb drive, and have two other drives to add to the server making 3 hard drives.

The two other drives I have are relatively small ; 6 GB and 8GB.

Disk for raid:
80 GB

The problem is I think in order to create a Raid the OS needs to create an even spanned volume ie :
5 GB
5 GB
5 GB

Is this correct?

If so Im losing space allowed for my RAID -5, or is 3-5 GB spanned volume RAID-5 enough?

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Software RAID is playing with fire..believe me

by Why Me Worry? In reply to Disk size for software RA ...

Unless you don't mind losing your data if one drive fails..even in a software RAID 5 stripe, I strongly recommend using a hardware based RAID solution that uses a real PCI RAID Array Controller. Windows software RAID sucks and is more trouble than it's me. I have lost data this way and having to waste 3 days restoring close to 4TB of data was not pretty.

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4TB on a Software RAID 5 Array???

by RaTTyRaTT In reply to Software RAID is playing ...

Are you strange? Why would you put up to 4Tb on a software array in the first place? Please tell me that you may have mistyped... That's like saying I put a petabyte of data on a SAN and never backed up. (U do backup don't you?)

BTW: hardware raid is the best, however you can use software as a 'poor man's RAID' and it still works, you just have to realize you cannot run your OS on the array. (At least if you want it to work that is in the event of a disk crash!)

Hope it helps!

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what r the options for hardware RAID?

by netforce In reply to Disk size for software RA ...

What would be the best options for hardware RAID.
My system is an old 232mghz server (really) what type of hardware RAID would be the cheapest route?


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Cheapest is not always best!

by wcox In reply to what r the options for ha ...

It really depends on your situation. If you're doing this for a "file and print" or test environment, ATA or SATA RAID can be a very inexpensive solution that should work well. If you're planning on hosting Exchange or a SQL/Advantage/mySQL/etc database then SCSI would be the way to go. Once you setup the array and start using it, upgrading to a better solution will far outweigh the costs of spending more in the beginning to get it right the first time.

Besides, would you want your client coming back and asking you why you recommended the solution that no doesn't work right? Just be careful...

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Would this be a better option?

by netforce In reply to Disk size for software RA ...

Found this on ebay:

Dual PIII 733 CPU's

256 MB RAM (Compaq Original)

2 - 9.1 GB 10K Hard Drives

Integrated 16mb Smart Array Raid Controller

Hot Pluggable Power Supply




NOTE: Also available for an upgrade option is an extra 2 bay hard drive cage that mounts in the two 5 1/4" slots for $20 extra.

This beats my 232mghz/128mb server by a long shot and I has the Integrated 16mb Smart Array Raid Controller.

Bear in mind this would be for a test lab/MCSE envirionment.

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i know him

by kd5oxm In reply to Would this be a better op ...

i know the guy that has that auction. the auction for proliant servers. thats is not ,by far, all ythat he has. iof it is the guy in dallas, he will talk to you on the phone for hours i met him last month. i have one of his dual p3 servers.

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Either way

by _Christian_ In reply to Disk size for software RA ...

Software or hadware, all should be the same physical capacity.

Otherwise you will end up with a raid drive the size of the smallest capacity drive.

Depending the hardware/software, mismatched capacities may also not be accepted at all.

So yes, your assumption is correct with your configuration, provided that the mismatch is accepted by your software.

At any rate , I agree with the comment that software RAID is playing with fire...

As for deciding if the size is correct, it depends entirely upon how much data you actually need to store. Nobody but you can answer that.

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by icealex In reply to Either way

above all you should also look for disk speed cause the slowest disk slows down the other disks to the same speed.
anyway, never use software RAID if you dont want trouble

cheers, Alex

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Software RAID, Good or Bad: It depends on the OS.

by badiane_ka In reply to Disk size for software RA ...

I was once working with a friend of mine who's windows guy and I was introducing him to Linux solutions which would help him start his business without incurring the initial expense M$ would have warranted. I suggested that he use software RAID and he instantly panicked and rejected the idea stating exactly what many of you guys are saying. The reason for this post is that when many of you windows guys talk about software raid you forget to say, M$ software raid, in order to differentiate it from the other OS (yes there are others in the world, however small their numbers are in contrast to M$). Take any of the BSD's and you will have security and stability up the wazoo.

I've seen Linux SA recover data from RAID 0,1 failures and there are some slight advantages to running your RAID 1, in terms of recovery, on software RAID.

Here are some links and please make an effort to investigate what else exists in the world before you start to define it within the limits of your understanding. The same applies to me. Though I do not like windows I understand its place in the world but my point has to do with placing limits on what human beings can develop and if one thing can be said is that we don't know what the future holds; so let us conclude our statements with "as far as I know".

Many of the RAID card provide a form of pseudo RAID to which Linux is superior (yep! that's right). So unless you are going to be using some 3ware stuff or other similar card, I would suggest using Linux RAID.

I'm going to be building a central storage system with a capacity ranging between 1.8TB to 2.4TB and using 3ware cards so that I can lower the load on the CPU with a XFS filesystem (,(,(
and instead of iSCSI I will be using AOE (ATA Over Ethernet), that way I take away the added TCP/IP complexity. I already have a small testing system installed with four 40GB USB drives (yes! I did say USB; why? Because I can) running software RAID5 (which hasn't fallen or crapped out yet) on an old 900MHz Optiplex, with VLANs and XEN virtualization.

It seems that I may be having more fun than you guys; at least if that's your thing.

Where I consult, they have company wide mail and file servers running on Linux RAID.

Here are some links: and search for raid.

I hope that you guys give the other OS's a chance. I know that one big problem with Linux is good documentation and at time simply documentation but more people get involved the better things get for all of us. The competition will hopefully force microsoft to be more competitive.

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