Green Hard Drive

[Old-Polack]

I just received the Seagate 2 TB Green hard drive I ordered Sunday. It's a 5900 rpm drive, which I planned to use strictly for backups, but before doing that, to see what difference the slow speed would make, I installed the full KDE release, and all the packages that I have on my regular daily use installation. I'm typing this from the installation on the Green hard drive. The drive itself is from Newegg, and described as;

Seagate Barracuda Green ST2000DL003
2TB 5900 RPM 64MB Cache SATA 6.0Gb/s
3.5" Internal Hard Drive -Bare Drive

I bought it because of the price, $109.99, which for a 2 TB drive these days is about as cheap as it gets. I had some doubts about this drive, because of various things I've read about problems with partitioning and operating systems running noticeably slower on Green drives.

So why am I writing about this, in a Tips and Tricks thread? Mostly because I'm absolutely tickled with this drive. I partitioned it with Linux fdisk, without any special attention to it being a Green drive, or going through the oft posted offset alignment rituals I've read about, because of the 4096 bytes sector size. Fdisk, in it's present version in our repo took care of that automatically.

I made a boot partition, a swap partition, installation / partition, and an extended partition, and left it at that.

[root@fatman ~]# fdisk -l /dev/sdc

Disk /dev/sdc: 2000.4 GB, 2000398934016 bytes
255 heads, 63 sectors/track, 243201 cylinders, total 3907029168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes                   <-- What can I say... Green drive.
Disk identifier: 0x18eee7ae

   Device Boot      Start         End      Blocks   Id  System
/dev/sdc1            2048     2099199     1048576   83  Linux
/dev/sdc2         2099200    18876415     8388608   82  Linux swap / Solaris
/dev/sdc3        18876416    81790975    31457280   83  Linux
/dev/sdc4        81790976  3907029167  1912619096    5  Extended

It may spin slow, but it moves dem bits n' bytes really quick. 

It's also very quiet, and runs much cooler than any of my other drives. Running the OS on this drive is virtually indistinguishable from running it on the 7200 rpm drives. I may have to stretch the budget and get another one of these critters.

The tip...? Oh yea!

Considering the grossly inflated hard drive prices generally seen these days, caused (or blamed) on the flooding in Taiwan, especially for larger capacity hard drives, the Green drives are about the only real bargain in town. (It seems lots of folks are just plain scared of them.) I paid exactly the same price for this 2 TB drive as I paid for my 1 TB drive when prices were considered "normal". That comes to 5.4995 US pennies per GB. That's cheap storage folks. 

[AS]

You told us a story       now please, show us the real numbers:

hdparm -tT /dev/sdc

 

[Old-Polack]

You told us a story     now please, show us the real numbers:

hdparm -tT /dev/sdc

 

It's my story, and I'm sticking to it.  

[root@fatman ~]# hdparm -tT /dev/sdc           <-- 2 TB Seagate green drive 5900 rpm

/dev/sdc:
 Timing cached reads:   8290 MB in  2.00 seconds = 4151.69 MB/sec
 Timing buffered disk reads: 400 MB in  3.01 seconds = 133.09 MB/sec

[root@fatman ~]# hdparm -tT /dev/sda           <-- 1 TB Seagate Barracuda 7200 rpm

/dev/sda:
 Timing cached reads:   8268 MB in  2.00 seconds = 4141.01 MB/sec
 Timing buffered disk reads: 354 MB in  3.00 seconds = 117.89 MB/sec

[root@fatman ~]# hdparm -tT /dev/sdb           <-- 750 GB Seagate Barracuda 7200 rpm

/dev/sdb:
 Timing cached reads:   8162 MB in  2.00 seconds = 4088.31 MB/sec
 Timing buffered disk reads: 300 MB in  3.01 seconds =  99.79 MB/sec

[AS]

That's Green drive is really good! 

[kjpetrie]

The optimum speed of a drive depends on the clock speed of the motherboard and the amount of cache available. The only advantage of a faster drive is that when data must be read from it that is not preloaded in the cache, the faster revs mean you might not have to wait so long for the appropriate sector to come round, but that depends on where the disc is when the need arises... Also, a long contiguous file will take longer to read if the bits aren't coming out so fast. The speed of reading will be the product of the angular velocity and the density of data, and obviously, a 2TB drive has double the data density of a 1TB drive, so the bits will be read and written twice as fast at the same revs (well, it's probably 1.41, as data density would be about area rather than linear ratios).

So it's not really surprising that a 2TB slower drive gives better performance than a 1TB faster drive. However, in most practical circumstances, the heads have to move to the right track, and that's where most delays will occur.

[horusfalcon]

The optimum speed of a drive depends on the clock speed of the motherboard and the amount of cache available. The only advantage of a faster drive is that when data must be read from it that is not preloaded in the cache, the faster revs mean you might not have to wait so long for the appropriate sector to come round, but that depends on where the disc is when the need arises... Also, a long contiguous file will take longer to read if the bits aren't coming out so fast. The speed of reading will be the product of the angular velocity and the density of data, and obviously, a 2TB drive has double the data density of a 1TB drive, so the bits will be read and written twice as fast at the same revs (well, it's probably 1.41, as data density would be about area rather than linear ratios).

So it's not really surprising that a 2TB slower drive gives better performance than a 1TB faster drive. However, in most practical circumstances, the heads have to move to the right track, and that's where most delays will occur.

Only thing I'd add to this most astute description is that some manufacturers (maybe more now than last time I looked?) use a constant areal density, so that data stored on the outer cylinders of the disk (which have more area and move faster) are accessible at a slightly faster rate than those toward the inner cylinders.  Some filesystems take advantage of this, but I'm not really sure if ext3fs does.

One last thing - that Green Machine is a nice buy, but I'd like to see it stack up speed-wise against a Seagate hybrid drive (which has a 7.2K hard drive with 32 MB cache close-coupled to a 4GB NAND Flash SSD in the same package).  Anybody got any numbers for one of those yet?

Later On,
D

[Old-Polack]

Just as an addendum to the original post, I recently tried to buy another one of the Seagate Green drives, and found they were out of stock, at the time, but also had a weekend special on the standard Seagate 7200 rpm 2 TB SATA 3 drive for $89.99, so I bought two of them instead. One is installed on the same computer as those listed in the OP, designated as /dev/sdd. Just to compare it to the green drive;

[root@fatman ~]# fdisk -l /dev/sdd

Disk /dev/sdd: 2000.4 GB, 2000398934016 bytes
255 heads, 63 sectors/track, 243201 cylinders, total 3907029168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes                     <--- Same 4 KB physical sectors
Disk identifier: 0xbbcb054b

   Device Boot      Start         End      Blocks   Id  System
/dev/sdd1            2048     4196351     2097152   83  Linux
/dev/sdd2         4196352  2101348351  1048576000   83  Linux
/dev/sdd3      2101348352  3907029167   902840408   83  Linux

...and to compare the speed of the new drive with those already reported;

[root@fatman ~]# hdparm -tT /dev/sdd                           <-- 2 TB Seagate Barracuda 7200 rpm

/dev/sdd:
 Timing cached reads:   8316 MB in  2.00 seconds = 4161.58 MB/sec
 Timing buffered disk reads: 490 MB in  3.01 seconds = 163.00 MB/sec

[scoundrel]

this is what I get with my WD Green TB's but think they are 7200

Code: [Select]

[root@localhost scoundrel]# hdparm -tT /dev/sda

/dev/sda:
 Timing cached reads:   1102 MB in  2.00 seconds = 549.80 MB/sec
 Timing buffered disk reads: 324 MB in  3.00 seconds = 107.83 MB/sec
[root@localhost scoundrel]# hdparm -tT /dev/sdb

/dev/sdb:
 Timing cached reads:   1080 MB in  2.00 seconds = 539.38 MB/sec
 Timing buffered disk reads: 276 MB in  3.08 seconds =  89.51 MB/sec
[root@localhost scoundrel]#


[jberkpc]

/dev/sdb:
 Timing cached reads:   26572 MB in  2.00 seconds = 13301.19 MB/sec
 Timing buffered disk reads: 536 MB in  3.00 seconds = 178.56 MB/sec
That's from my 1TB WD VelociRaptor
I personally had really bad luck with Seagate. I bought 3 of their drives for different builds and only one still runs. The 1 TB version I bought lasted about 6 months and the replacement I received, ( a rebuilt) smelled of burnt electronics and is in the closet some where.
Everyone has their horror stories about different brands of Hard Drives, but for now I'm staying with WD.

 

[dixonpete]

I have 2 Green WD 2TB drives and one Green Seagate 2TB in my media machine. The Seagate drive is very noticeably slower than the WD, or at least much slower to wake up.

Never had an issue using the WD as the boot drive despite hearing similar warnings. These were bought back when they were as low as $69 each. Those were the days..

[Old-Polack]

I have 2 Green WD 2TB drives and one Green Seagate 2TB in my media machine. The Seagate drive is very noticeably slower than the WD, or at least much slower to wake up.

Never had an issue using the WD as the boot drive despite hearing similar warnings. These were bought back when they were as low as $69 each. Those were the days..

Define "slower to wake up". Wake up from what?

[dixonpete]

A count of 14 till the directory loads compared to a count of 4 for a similarly loaded WD drive. This is with probably 1500 dirs and 500 files each. Been that way ever since I set up the system. To be fair the drives were bought about 2 years ago. Things may have changed.

[Old-Polack]

A count of 14 till the directory loads compared to a count of 4 for a similarly loaded WD drive. This is with probably 1500 dirs and 500 files each. Been that way ever since I set up the system. To be fair the drives were bought about 2 years ago. Things may have changed.

I can't relate to that, in any way. I click on a directory, and it is open immediately on the upstroke. Are these drives internal or external? How are they partitioned?

[root@localhost ~]# fdisk -l                      <Enter>

Post your results.

[dixonpete]

Won't be posting anything for awhile since I just left home for a week's vacation.

The Seagate I know is is simply a single volume. It has upwards of 2000 movies on it, 1500 folders and 500 single avis/mpgs. The WDs drives have similar contents but load much faster.

The speed I mentioned refers to the time to load that massive listing.

[Palko]

I don't know...
My old Samsung hd753l have:
Timing cached reads:   22734 MB in  2.00 seconds = 11381.92 MB/sec
Timing buffered disk reads: 336 MB in  3.01 seconds = 111.60 MB/sec