Cloning a RAID array

[Starrx05]

Hi everyone, I have an old dual P3 1Ghz Supermicro board and 2GB of RAM. It has built-in Promise RAID, their FastTrak100. I'm planning to set up RAID 0 on 2 80GB HDs, put OS on it and clone to a 160GB HD in a mobile rack in case something goes wrong, I can just use Ghost to restore. Is it possible to clone a HD like that? I heard that RAID 0 gives some performance increase but double the chance of HD failure but I don't understand why that's true all the times because each drive only does half the work in read/write, so half the wear and tear.

Also, if I set them up as RAID 1 for mirroring, will there be any performance increase in reading or just it's an extra drive backup in case the other fails? Will the controller read half of data from each drive or it will use just drive 1 leaving drive 2 unread? I understand, this won't protect me from accidental delete/overwrite so I will have to do real backup each week anyway. Sorry if my questions is too basic or someone already asked it. I haven't tried out RAID before and it seems to be a waste if I leave it unused on this board. So my plan will probably be 2x80GB on RAID 0 for OS, one HD for apps/data and mobile rack for backup the OS & data plus 2 DVD/CDRW drives. Or I can go 1x160GB for OS, 2x80GB on RAID 1 for apps/data and the mobile rack to backup really important things to store outside somewhere. I'll be using the system for graphics like Photoshop, burning DVD/CDs, listening to streaming audio/video, downloading large stuffs. Most of the times, I won't be at the system typing, moving the mouse around. I mean, I will let it run doing what I need in the background then switch to another system (I have a KVM switchbox) so I need it to be stable more I think if cannot be really fast. Yah, I know the system is old now and it doesn't have SATA ;-( What do you think? Thanks for all inputs.

 

[Jiggz]

Yes you can just use Ghost to clone the RAID 0 on a regular basis to ensure you have a back up. As for the mirror RAID, no there is no performance increase instead you will have a real time back up of the OS hdd. As for the performance increase with RAID 0, that is very subjective depending on what you will use your system for. One thing for sure, you will notice increase performance in load times and also boot times. Anything else is subjective. I ran RAID 0 with 2 X 80 GB for almost two years and then using a 160GB as a back up. I only back up when I have signifanct data or programs added to the system. And the back up 160 hdd is always disconnected unless I am doing a back up. Sure it's a PITA but it minimizes wear and tear.

 

[Starrx05]

Thanks Jiggz, for your response.

I'll go with the RAID 0 setup. 2x80G's for OS and 1 160G for app/data. I have 2 extra 160G's for cloning and backup of the OS and data drive. I risk a bit more with having one of the 80G's fail but I can quickly get another 80G and clone the whole thing back. At least it's faster and re-install all my apps. The only bad thing with this set up is 160G to put OS and main apps is a bit over kill for me. 80G total is more than enough but I don't have 2 40G's. I often thought mirroring would double read time bcos the controller could read from both drives at same time but it looks like I've been wrong. I still have to do backup on it to avoid accidental delete and virus so it doesn't help much. For people who need 24/7 up time, mirroring might be a better choice though bcos they can run off one drive while finding a replacement.

Oh well, I might get rid of this system for all and get a 3Ghz P4 but cost-wise it might not be good for me. I need to get new RAM and I don't think I'll get much for this dual P3 board. It was a very good mobo retired from a server back then. The only thing I don't like about it will be the noise. There's no place to put 2 80mm fans on the heatsinks, only 60mm ones so they will be noisy together. I have the Antec 3700BQE quiet case. Hope it will block some of the noise. Anyway, thanks again for your reply & advice.

I forgot another question, in the RAID setup, they let me choose block size and it ranges from 4K up to 64K. I don't know what to pick for 160G total. I know smaller block size will save disk space but will increase read time if I have more small files than large ones (?) Maybe I just go with the middle choice, which is 16K, then change to a smaller size to see if there's any difference in performance.

 

[Jiggz]

According to test conducted, the most efficient block size for a RAID 0 is 32K. You do not have to use the entire raid as an OS HDD. You can partition it into at least two or three depending on your liking. I had mine partitioned into 60 Gb and 100Gb. I use the 60 GB as the os hdd while the 100 as storage. I also place the page file on the 100 GB partition.