DescentBB

Hi everyone

Well the time has come for me to expand my storage space as I just filled my 1.5TB HDD on my file server.

Now with my server rebuild I was always planning on building up a RAID 5 setup for my file server storage needs (redundancy and overall space vs number of drives needed). I've been browsing between my options and pricing but the WD 2TB drives I looked at I found horrible feedback of drive failures (Caviar Green Family).

So the advice I need is what HDD should I look at if the following is my criteria

RAID 5 setup
Max 6 HDD can be setup in RAID 5 on this motherboard (leaning towards 6x2TB to give about 10TB)
Should be fast but the main use is storage of my files so access time should be adequate but I'm movable on a few milliseconds but transfer rate is the key as I'm looking for max transfer rate as far as possible (running a gigabit network).
Should not require me to go get a mortgage loan

Things I know:
SATAII vs SATAIII on HDD is a mood point as SATAIII is only really relevant on SSD's
As I understand the HHD's will most likely be the transfer rate bottleneck on my network in any case

Things I'm not sure off:
RPM speed, relevant for my needs? Looking at pricing here as 5900RPM drives are considerably cheaper than their 7200RPM counter part but if it's gonna cost me on transfer rate I'll consider spending more. But reading the manufactures site of the 5900RPM drive Sustained data transfer rate is stated as 95Mb/s which is more than my current transfer speeds I average over my network as I'm not sure of the current HDD's specs and the 7200RPM is listed as 138Mb/s. Question is basically will I get these speeds on my network in a RAID 5 setup were I to go for the 7200 option or are there other bottlenecks that will negate the stated speeds?

Anyways looking for inputs here to get the right stuff of hand instead of wasting money on cheap stuff and costing me more trouble in the long run.

Thanks in advance

You do understand that RAID5 is also a stripe of the data on multiple drives so the sequential read speed from say a 5 drive array with a 95 MB/sec transfer PER DRIVE is likely to break 400 MB/sec at the host?

Just one drive is generally enough to saturate gigabit LAN (80-120 MB/sec depending on the protocol overhead), any array is all but guaranteed to saturate gigabit LAN in any sizable sequential transfer even if it is reading from the slowest inner tracks of the drives. A 6 drive array with 7200 RPM drives would be well on its way to saturating current implementations of 10 gigabit LAN... On the other hand latency in RAID arrays is terrible regardless of what type of RAID it is, when you have to randomly seek around on multiple drives in order to spit something out the latency is always going to be the worst case scenario.

As far as reliability goes, I've seen dead Seagates, dead Western Digitals, dead Hitachis, dead Maxtors, dead IBMs, dead Samsungs, etc, etc, etc... Pretty much take a sample of any 5 hard drives from a brand and one of them will fail within a year or two of operation. I can just about guarantee you will experience some failures on a 5-6 drive array if you run it for a couple years. Don't listen to people suggesting one brand is more reliable than another, because they aren't. Statistically Hitachi drives actually stick around the longest, but this has less to do with them being more reliable and more to do with them being widely used in the enterprise sector where they are kept in service for 5+ years. There are occasionally particular models from one brand or another that have a common and fatal flaw (early Seagate 1.5 TB drives had defective firmware that bricked the drives, the famous IBM DeskStar, etc), but if you average every brand and model out the failure rate is about 5% per year across the board for mechanical drives.

The only part about the reliability of the drives you should pay attention to is the length of the warranty. Seagate, Western Digital and Hitachi all offer certain drives with 5 year warranties, I would suggest sticking to the drives with long warranties like that because when you build a larger array like that the odds of encountering a failure within the warranty period skyrocket and the longer warranties will come in handy.

Thanks for the info, forgot that the raid will effectivly increase the transfer rate. Will make a point of checking the warranties too. Also it would seem to me that I also need to steer clear of these "green" drives as they don't go well with raid setups. So I be looking more towards the WD Cavier Black or the seagate SV35 or XT range. Guessing it will most likey come down to best value per TB between these drives then as they are more or less in the same price range besides the SV35 but they look to be 5900rpm drives but not "green" tech.

[EDIT]
Okay browsing around a bit more and considering that the RPM for overall transfer rate purposes in a RAID5 will sort of be irrelevant as the gigabit lan will be saturated in any event in a 6 drive array I'm now leaning towards the following drive.

SV35 Series™ Hard Drives
Reasons:
Price (they are a lot cheaper than the Seagate XT or WD CB of the same size)
Lower RPM = less noise and less power consumption, less heat & Transfer rate of a 5900 vs 7200 HDD will be negated in RAID5 setup but all the same this drive is rated at 144mb/s
Seek and write specs are more or less the same than my other options
They are build for 24x7 operation
5 year Warranty
But most important I think is this Comparison Sheet where the SV35 is stated to support RAID5, even thou the 2TB SV35 isn't specifically listed I can't see why it won't be able to support RAID5 if the lower size models does.

Any thoughts on the above?