Different sized disks in RAID 10 array?

[dan_aka_jack]

Hi there,

I have an existing RAID 10 array consisting of 4 x 500GB disks (making a 1TB RAID volume). I need to expand my array. Can I add 2 x 750GB disks to make a 1.75TB volume or do I need to add 2 x 500GB disks?

My RAID controller is the Intel Matrix RAID built into my P35-based mobo. It doesn't support on-line expansion of RAID10 arrays so I will have to backup all my data, delete the existing 4-disk volume, create a 6-disk volume and restore all my data.

Many thanks,
Jack

 

[rpstewart]

You won't be able to use 4x500 & 2x750 to make a single 1.75Tb RAID10 array, all the volumes need to be the same size. You either need to go for a 6x500 array or you could use the wackiness of the Matrix RAID and split the 750s so that you have a 1.5Tb RAID10 array across 4x500 and 2x500Gb partitions on the 750s then RAID1 the remaining 250Gb on the 750s.

 

[dan_aka_jack]

Hi, thanks loads for the reply RPstewart. Frankly, you are the Storage Saviour! I've lost count of the number of my questions you've answered - and usually within a matter of minutes. Thank you.

OK, I think I will go for the 6 x 500GB option. Although I'm now wondering if I should really sting my bank account and buy an extra 4 500gb drives for an 8-disk array.

However, the P35 only has 6 SATA connectors. But, as I understand it, all 6 of those ports are eSATA-enabled and eSATA supports port-multiplying. So, could I in theory connect a port multiplier to each of my mobo's SATA connectors to allow me to connect up to 30 SATA disks (6 SATA ports on mobo x 5 ports on each port-multiplier)?!? SerialATA.org seems to suggest that I could get away with this setup.

Of course, connecting 5 disks to a single SATA-II pipe probably wouldn't perform very well because 5 disks would almost certainly saturate a single SATA-II pipe. But I figure I should be able to connect about 2 or 3 SATA drives to each of my mobo's SATA-II connectors if needs be to allow me to expand to an 18-disk RAID array if I really wanted to!