RAID 5 expansion question

[gkwok]

Hello everybody...I'm thinking about setting up an IDE-RAID 5 system with an Adaptec 2400A both for speed and redundancy. That way I would not have to back up to CD-RW as often, which takes me about 4 hours. I am a bit concerned about the expandability of RAID 5 though. Currently when I upgrade my hard drives, I use Partition Magic and move everything on my larger hard drive to the new (even yet larger) one, and everything from the smaller hard drive to the old larger one, and get rid of the smaller one. But say, for example, I get 3 60GB hard drives, providing me with 120GB of usable space. What happens if, say a couple years from now, 120GB is small and .5TB or something is the norm. Is it possible to take out one drive of the array at a time, stick in a new larger one, let it rebuild, and repeat for the remaining two drives? Or would the controller only use the first 60GB of the disks you put in? Basically I just want to know if an in-place upgrade of all three drives simultaneously is possible (even if it is over the course of several hours), or if I would have to back up the whole array to CD, and create a new array from scratch, and restore from CD. I've read StorageReview's RAID guide but could not pull out a definite answer to my question there.

Thanks in advance.

 

[BurnItDwn]

hmmm this is a good question, I do not think it will work, But i have never tried, so perhaps i should have kept my mouth shut.

In theory it would work, until the point came when you had all three of the larger drives. In which case, you would need to re partition the drives to make use of the added space.

A different (and also not guaranteed) solution, would be to add the new array as a seperate array, then use Ghost, or another Disk imaging proggie, and mirror the old array into the new array, then when yer done, just pop out the old drives. In order to do it this way, you would need to buy another Raid card though, Which may cause some IRQ conflicts, and may cause you trouble if you use 2 of the same raid card, or try to remove an array and switch it to another raid controller..

Just my thoughts on this issue

 

[asiagian]

You can replace HDD with larger capacity, but it will only use the same capacity as your current config (60GB), rest is wasted. Even if you re-create the array, it will only create 120GB of space, unless you change those 3 HDDs. That is the concept of RAID 5.
The only way is to backup the whole thing, replace those 3 HDD with larger capacity, create the array and restore your data.

 

[Zach]

Yeah, if you stick a 100GB drive in an array of 40's it'll only be 40% used. THe rest is unused.

Just plan on getting new hard drives at the same time. Besides, if you make a big badass RAID 5 array, by the time you need to upgrade it your HD's and RAID card will be old and slow!