Adding an Extended Partition

[Andrew Kaplan]

How would I, if there is a way, add an extended partition to a RAID 5 array that already has four primary partitions?

[Francisco J. Soler]

Hi Andrew,

If the RAID 5 is hardware controled, the linux box only detects a big hard disk, so i think you can add it with fdisk, this means to destroy one of 4 primary partitions.

Frank.

[Stuart Browne]

Frank's right.

You can only have 4 partitions on any given disk.

An extended can have 4 'logical' partitions.

Go good 'ol DOS limitiations ;) Much fun.

[Stuart Browne]

Frank's right.

You can only have 4 partitions on any given disk.

An extended can have 4 'logical' partitions.

So yea, backup one of your partitions, destroy it, create an extended, then some logical's under that.

Go good 'ol DOS limitiations ;) Much fun.

[Andrew Kaplan]

Since I can't add an extended partition without removing one of the primary partitions, I had an alternative in mind. My plan is to delete one of the primary partitions, and then use fdisk to create an extended partition. Once that is done, I would then create several filesystems within the extended partition. I would then repeat the process for one of the other primary partitions. My ultimate goal is to have two primary partitions, and two extended partitions which, in turn, would have several filesystems within them. Is this feasible?

[Jeroen Peereboom]

No, you cannot have 2 extended partitions on 1 'disk'.

There are at most 4 partitions, either:
1,2 or 3 primary and 1 extended partition
or
4 primary

You can create logical partitions in the extended partition.
Numbering is as follows:
primaries: 1, 2, 3, 4
extended: 4
logical: 5, 6, ...

JP.

[Andrew Kaplan]

If I create the extended partition with the logical drives within it, is it possible to extend its size further and add additional logical drives if I opt to delete a second primary partition?

[Jeroen Peereboom]

Andrew,

fdisk certainly won't do that for you.
I don't think Diskdruid has such an option. It would involve moving logical partitions.

I have had a bad experience with PartitionMagic, which can do the job for you, which didn't work well with Linux.

Are there other (Linux) programs to shrink filesystems / (primary) partitions?

You'll have to try and move data from a primary partition to somewhere else: another primary partition? Another disk? Tape?.

To be honest, I've not done many such things on Linux. Always used Partition Magic, till I got Linux problems with that.

JP