Replacing 7200rpm drive with 5400rpm drive

[DesignTactics]

Hi all -

we have a ReadyNas NV+ which was originally configured with four 1TB Seagate ST31000340AS drives when first purchased three years ago.

The first two drives have failed in the last month, and we're now getting growing SMART errors in the third.

Reading up on the drives that are failing, I'm not happy to replace them with another Seagate - which is what we did for the first two. (We used ST31000322CS Seagates to replace the first two failures.)

I'm also conscious that we're trying to find four 1TB drives at a time when they've never been so expensive.

Given both these factors, I'm considering a switch to a Western Digital drive WD10EARS - this on the approved hardware list, but is 5400rpm compared to the 7200rpm Seagates.

Is it possible to mix drive speeds in the ReadyNas NV+?

Is it advisable?

Many thanks...

[PapaBear]

It is possible. Sometimes, it seems to offend our sense of order, but as long as the drive is on the approved list and stable, there should not be a problem.

I have mixed 7200 and 5400 and different brands and size drives on my two NVX units and the response may be a little slower than on all 7200 RPM drives, but not really noticeable. Since the NV+ has a lower transfer speed than the NVX, the difference in drives should not be noticeable.

On my NV+, I started out with two ST3500630AS drives over 4 1/2 years ago and within a month one died. I replaced it in kind and it was replaced by Seagate with a 750GB drive. I ran with the two 500GB drives for years but then it started filling up (video sure eats drive space). I had purchased two Samsung 500GB (HD501LJ) as spares after I lost that first drive and my first expansion was with one of them. However, when I tried to add the second to go to 4 drives, it was rejected, and I wound up using that 750GB drive. The unit ran this way for almost a year when I upgraded it to 1TB drives (after I got my first NVX). When removed from service, the two ST500630AS drives had over 24,000 Hours on them. They are still in backup service today.

[DesignTactics]

Thanks for that info, PapaBear - It must be something else that is causing our ST500630AS drives to fail so systemically... I since found a better price on the ST31000322CS, so I'm going to stick with that for the moment. The savings to the slower RPM drive was in the region of €20, so it wasn't that bad.

[PapaBear]

Well, your failure of two of four drives after 3 years would in my mind be considered early, but you still would have had about 24,000 hours on them. Keep in mind that this was 24/365 use, far in excess of what one would see if they were in a PC for example. My one failure in the first months would be considered premature, but some in this forum believe that many of the premature failures, especially in clusters are possibly the result of rough handling during shipping.

It is not a question of whether a drive will fail or not, it's a question of when. In reality, I have had better service from my drives in the NAS service from a pure standpoint of hours than almost any of my drives in PC usage. Since I do not leave my PC's on for 24 hours a day, and when working they were all off while I was gone, I would say that I typically put less than 1,000 hours a year on any of my PC drives. A drive in an NAS that runs for 24 hours a day at the end of a year will have accumulated about 8,700 hours. I would doubt that I would ever accumulate that many hours on a PC drive, because it would take about 8 years to get there, and by then, even if I'm still running the PC (unlikely), I would have upgraded the drives.

This is why, many people set their NAS units to spin the drives down after a period of inactivity.

[DesignTactics]

We've had an unusual run of failures - we had two (external) LaCie 2tb drives fail within a year of each other - and when we replaced that with a Drobo (sorry!) one of the drives in that device failed in the first 24 hours. All this happened on the same desk - think it must be some kind of magnetic voodoo curse...

Thanks for the reply!

[PapaBear]

Drives are like light bulbs in that they may fail when you first turn them on, or may run for years. (Of course there are two light bulbs that I have hear of that have been burning for 90-100 years.