Review of Seagate's 750Gb Hard Drive

Zoxed writes "The Tech Report have a comprehensive review of Seagate's Barracuda-7200.10 'perpendicular' drive, including a primer on the technology. They ran performance tests against 10 other drives, checking the noise and power consumption levels. The Seagate fared pretty well, even on cost (per Gigabyte)." From the article: "Perpendicular recording does wonders for storage capacity, and thanks to denser platters, it can also improve drive performance. Couple those benefits with support for 300 MB/s Serial ATA transfer rates, Native Command Queuing, and up to 16 MB of cache, and the Barracuda 7200.10 starts to look pretty appealing. Throw in an industry-leading five year warranty and a cost per gigabyte that's competitive with 500 GB drives, and you may quickly find yourself scrambling to justify a need for 750 GB of storage capacity."

Comments

Get perpendicular :D

[LiquidCoooled]

http://www.hitachigst.com/hdd/research/recording_h ead/pr/PerpendicularAnimation.html

Watch out for the superparamagnetic effect though.

Re:Big HUGE warnings

[Dan Ost]

No, this isn't true. If the failure rate of drives is constant (pretty close to reality), then
if you've got 7 drives and I've got 1, you're seven times more likely to lose a drive than
I am.

Granted, you only lose 1/7th if your drive fails, and I lose all of it, but since we're both
making backups (you ARE making backups, right?), you're paying 7 times the space, electricity,
heat, and noise costs for less reliable storage than I am. Assuming that we both run out systems
long enough for drives to fail, you're also paying 7 times as much of your time replacing drives
than I am.

What sense does that make?

Re:Whoah

[Martin Blank]

You just have to look for them a bit. I just picked up a 300GB Maxtor SATA-2 with 16MB cache and NCQ that has a 5-year warranty, and it only cost me about $6 more than the 3-year warranty version with identical specs. Other companies may also offer them. (Of course, Maxtor is now a part of Seagate.)

Bad math..

[JMZero]

If you've got 7 drives and I've got 1, you're seven times more likely to lose a drive than
I am.

Let's say each drive has a 20% chance of failing. So if you have seven of them, do you have a 140% chance of one failing? Of course not. What you really have is 80%^7 percent chance of them all remaining OK. 80%^7 = 21%. Thus you have around a 79% chance of failure with 7 drives (if they all have 20% failure rate).

Your point still stands - but I noticed pretty much all of the replies to this guy used the same bad math.

Re:Bad math..

[enrevanche]

Not true, if you flip a coin 3 times are you 3 times as likely to get a tail. i.e. do you have a 150% chance of getting at least one tail? no you have 1 - 0.5^3 = 1 - 0.125 = 87.5% chance. There is 12.5% chance that you would get no tails. With drive failure it works the same way, you have a chance at no failures and also a chance of multiple failures.

7 times as many failures (over a large number of samples) is not the same as 7 times the chance to have a failure.

Re:Bad math..

[pla]

Thus you have around a 79% chance of failure with 7 drives (if they all have 20% failure rate).

IF you have a 20% failure rate.

It cheats somewhat to use that as an example, however, because with the real probabilities involved, you approach a linear trend with the number of drives.

Let's try an MBTF of 50k hours. That gives us a 0.002% chance of failure per hour. Take 0.99998 to the seventh, and we get 0.9998600084... Or "seven times as likely", accurate to better than one part in a thousand.


Though, I will admit doubt that the GP explicitly took that into consideration in his statement. ;-)

Re:Scrambling?

[drinkypoo]

Any firewire bridge that has the right interface to speak to the drive should be able to talk to it just fine. This isn't the old dark days of DOS where you needed extender software just to talk to fancy new drives. Since drives use logical geometry to talk to the host adapter, this just isn't an issue any more.

Re:Scrambling?

[Fweeky]

Anything supporting LBA48 should handle it just fine, although we're rapidly approaching the 2TB limit many controllers have on a single disk/array. LBA48 supports drives up to 128PB (512 byte blocks * 2^48), but of course we're still in a largely 32bit world, so it's more like 512*2^32 unless you're careful.

Re:Big HUGE warnings - Not quite true

[swillden]

RAIDing 7 or 8 drives would be quite a task, while doing 2-4 drives is relatively easy.

For those who don't see the difference: Most boxes don't have controller capacity for more than four drives (two PATA channels and two SATA channels) and seven or eight drives will also strain your PSU and your cooling capacity. Might be hard to fit in your case, too.

Of course, once you solve those problems, actually setting up the RAID is no different whether you have three drives or 30. A little more typing, maybe.

My file server has six disks in it, BTW, so I've worked through all of this. I can easily add a seventh without any trouble. An eighth would require a new controller card. I'm not sure how many drives I can add before my 550W PSU starts to have trouble. My cooling solution is low-tech, loud and very effective: The side of the case is off and I have a 30-inch box fan (the kind you mount in a window to cool your house) blowing into it.

One nifty trick I discovered is that if you slice all of your disks up into many small partitions, then create many RAID-5 arrays (using partition 1 on each disk to create the first array, etc.), then use LVM to bind all the arrays together you can add additional disks and rebuild the arrays without having to find some way to back up all of the data first.

I just added a 500GB drive to my system and I'm in the process of changing all of my four-disk RAID-5 arrays to five-disk RAID-5 arrays. The process works like this:

1. Use pvmove to migrate all of the data off of an existing four-disk array.
2. Use vgreduce to remove the now-unused array from the volume group.
3. Use pvremove to remove the LVM superblock from the array.
4. Use mdadm to stop the array and clear the md superblocks on the partitions.
5. Use mdadm to construct a new five-disk array from the four partitions that made up the old array, plus a fifth partition from the new disk.
6. Use pvcreate to add an LVM superblock to the array.
7. Use vgextend to add the array into the volume group.
8. Go back to step 1 with the next four-disk array, until they've all been converted.

This assumes Linux, obviously, is a bit tedious and requires that your LVM volume have enough free space so you can drop an array out of it. It's a whole lot easier than trying to figure out how to back up a TB+ of data so that you can rebuild your array, though. In my case, there's an additional step right after step four -- because my new drive is SATA and Linux doesn't support more than 15 partitions on an SATA drive, I'm moving from using 20GB partitions to 40GB partitions. So after I kill each pair of four-disk arrays, I repartition the drive to merge the partitions.

Let me tell you... repartitioning all of the disks holding my data made me more than a little nervous at first :-) I kept backups of the partition tables, just in case, but it actually worked just fine. Next time, though, I think I'll just create a single partition and use LVM to chop it into pieces which I can RAID together. So I'll have LVM over RAID over LVM. Sounds weird, but it makes a lot of practical sense.

Re:The real reason why this drive is great

[ars]

I'll give tou two tips:

1. Preview

2. Go into your prefs and change Comment Post Mode to 'Plain Old Text'.

Re:only 187 million times cheaper per bit

[WuphonsReach]

$413 sounds pricey until, as you noted, you do the math for the $/GB amount. For being a leading-edge drive, the price per GB is rather competitive.

The following prices are estimates based on www.pricescan.com. There could be as much as +/- 10% variation in prices.

PATA drive prices
120GB $64 - $0.53/GB
160GB $70 - $0.44/GB
200GB $75 - $0.38/GB
250GB $80 - $0.32/GB
300GB $105 - $0.35/GB
400GB $195 - $0.49/GB
500GB $260 - $0.52/GB
750GB $490 - $0.65/GB

SATA Drive prices ($/GB)
120GB $68 - $0.57/GB
160GB $65 - $0.41/GB
200GB $76 - $0.38/GB
250GB $80 - $0.32/GB
300GB $105 - $0.35/GB
400GB $175 - $0.44/GB
500GB $250 - $0.50/GB
750GB $434 - $0.58/GB