Is a Raid0 Live Partion Possible?

[GwarGor]

I have 2 SATA2 hard drives in a raid0 config and want to know if it is possible to make a partition on it using the free space available on the drive without affecting the data on the drive right now. I've done this with Partition Magic before on a single drive without a problem, but not with 2 drives in Raid0. The readme for Partition Magic says that it can't do it, but is there other software that can?

 

[sabregen]

Windows and most all other OS's can do it, but that is only if you're referring to setting up a partition from unused free space. If you're talking about taking already partitioned space that isn't being used, not even Partition Magic can do that.

 

[GwarGor]

I am talking about using unused space from disks (2) in a raid zero and use the free space to make a new partition without affecting my other data that is on the Raid0 array.

 

[sabregen]

You are SOL. with RAID 0, not only is there's a partition table on each disk, and in RAID0, that means that you are writing alternating bits to each drive, hence the performance increases. However, you have to define RAID 0 partitions before any formatting occurs. Even if there was a software app that would "do" it, I wouldn't trust it at all. You'd likely end up having to re-partition manually anyways. I think most software companies COULD do it, but they know that they likelyhood of dataloss from re-writing two partition tables simultaneously without the advantage of an ASIC with battery backed ECC cache is a recipe for disaster. Hard drive recovery by companies that specialize in it cost close to $2k per disk...that's why the desktop solutions don't do it. Not even hardware RAID cards will resize defined RAID 0 partitions.

 

[GwarGor]

I thought as much, not the end of the world, but a big PITA....I'll manage, just will be more time consuming moving my stuff to my other drives and freeing up space to move the stuff. Thanks for your reply...

 

[pc299]

Are you talking about resizing the partition and adding a second in the leftover free space? If so then partition magic or another disk utility should be able to do it.

 

[sabregen]

He's talking about resizing to add a second partition on a RAID 0 with a partition manager program.

 

[unhappy_mage]

with RAID 0, not only is there's a partition table on each disk, and in RAID0, that means that you are writing alternating bits to each drive, hence the performance increases.

You're confusing things a bit. Raid 0 alternates blocks, not bits or bytes.

Even if there was a software app that would "do" it, I wouldn't trust it at all. You'd likely end up having to re-partition manually anyways.

I disagree. Software is pretty capable, in the general case.

I think most software companies COULD do it, but they know that they likelyhood of dataloss from re-writing two partition tables simultaneously without the advantage of an ASIC with battery backed ECC cache is a recipe for disaster. Hard drive recovery by companies that specialize in it cost close to $2k per disk...that's why the desktop solutions don't do it.

This is a muddle of terms. Why would writing a partition table to two disks cause a problem? It's only 512 bytes or something...

Not even hardware RAID cards will resize defined RAID 0 partitions.

Partitions are a higher level abstraction than RAID creates. The RAID card would never be responsible for creating partitions.

To the OP: Unfortunately, I think backing up and restoring will be necessary. Raid 0 is unlikely to be hardware RAID, but you can try PartedMagic to see what's visible.

 

[GwarGor]

o the OP: Unfortunately, I think backing up and restoring will be necessary. Raid 0 is unlikely to be hardware RAID, but you can try PartedMagic to see what's visible.

Yea...Was just checking ...it's cool, just a PITA

 

[sabregen]

You're confusing things a bit. Raid 0 alternates blocks, not bits or bytes.

This is a muddle of terms. Why would writing a partition table to two disks cause a problem? It's only 512 bytes or something...

Partitions are a higher level abstraction than RAID creates. The RAID card would never be responsible for creating partitions.

1.) Yes you're right. Blocks

2.) It is a very small amount of information, but most partition managers are operating at the file level, and not at the block level. File level partition programs essentially do a copy of files to unused space that is inside the targeted partition size, then rewrite the tables. You'd need a block level program to do that, and most partition managers do not support RAID levels.

3.) The RAID card is responsible for initializing the disks, and keeping track of the disks that are members of the array. You are correct, they do not create the partitions, but do keep track of their member disks, and hopefully their SMART status as well.