Mixing RPM drives in RAID 5?

[smidley]

Hey guys, I have 5 Hitachi 2tb 7200RPM drives in a RAID 5. Am I able to add another 2tb drive that has a lower RPM rating to this RAID set? Will I have issues of any kind? Do the 7200 RPM drives just spin at a lower rate? If someone could explain to me what would happen in this type of situation, that would be great! Thanks.

I'm currently using a dell Perc 6/i controller with BBU.

 

[nitrobass24]

The other drives would work at 7200 RPM still but your I/O is going to be limited when it has to wait on the 5400RPM drive. It will basically slow down the array in terms of Random IO and access times, but should not really affect sequential read/write access. I would just make sure the drive is compatible so you dont have drive timeouts and the array fails.

 

[smidley]

Ok, the ones I'm looking at are the new hitachi ones. The 5K3000 series drives. I'm assuming those are compatible.

 

[Patrick]

I would just offer that mixing drives (especially of different speeds/ generations) is not considered best practice. Some people successfully do it, but one should recognize that there is additional risk involved. Speed wise, as nitrobass24 mentioned, the array will be limited by the slowest drive. While sequential speeds are competitive between the 7K2000 and 5K3000, the random I/O times are going to be different.

 

[smidley]

Thanks for the info guys. This is just for my home server, and not for a work production environment. It will be used to store video and music for streaming over the network.

 

[odditory]

Like Patrick said, not best practice generally speaking, but if there's any exception to that rule it would probably be with the Hitachi's, especially considering the 5K3000's push even higher sequential I/O than the 7K2000's, whereas historically speaking 5400RPM drives haven't performed up to the level of their 7200RPM counterparts.

I figured this was going to be a fairly common question, and one we'll continue to hear about, with all the people that bought into the 7K2000's and now want to expand but are finding the 7K2000's hard to get for a good price. I'm going to mix my 8 x 5K3000's into one of my backup arrays and see if it doesn't break anything.

It would be a good idea to get Hitachi 7K2000's firmware updated to latest 3MA, I'll be posting a dedicated thread on that this week.

 

[dscline]

It would be a good idea to get Hitachi 7K2000's firmware updated to latest 3MA, I'll be posting a dedicated thread on that this week.

Hi, I'm new here, found this googling (though I do have a WHS, so this should be a worthwhile place to check out anyway ). But right now, I'm specifically interested in the firmware update for the 7K2000 drives. I have four of these in my server, and they essentally can't be defragmented. For some reason, there seems to be some incompatibiliby between them and PerfectDisk. When I try to defragment them, they grind on for days on end, while all the others complete in a couple hours. Raxco had no solution, and suggested contacting Hitachi for a firmware update. Hitachi sent me a firmware update (after a week or two of back and fourth emails), along with their HiTest software to flash it with. This software is HORRIBLE. It doesn't see ANY of my drives, and on several occasions "scanning" my system has caused my server to BSOD. I've emailed them and asked them if they had a simple DOS based flashing tool (like most use), but as of yet I've been unable to get anything other than this horrible windows software out of them. I assume the firmware they sent is the same as the one you mention (mine is named JK0NB3MA.BD). Do you, or anyone, have any other tool to flash these with?

Thanks!