Hello, On Mon, 07 May 2012, phanisvara das wrote:
On Mon, 07 May 2012 02:44:39 +0530, David Haller <dnh@opensuse.org> wrote:
The WD is a 500G PATA model. And the others were bought over ~2 or more years, with a couple months inbetween. Above mentioned Seagate-Samsung is in the other box, replacing a WD 20..EARX? and a Seagate ST1500xxxAS.
so you're using both, seagate & samsung green variety, with good results. perhaps i'll better wait for somebody coming over from US, which will happen sooner or later, and ask them to bring one or two (once i get the money approved, that is).
Not sure if the (real) Seagate ST1500...AS are "green" models. The WD 20...EARX in the other box is a "green" one too. Basically you have 3 kinds of drives today: - server drives (specced for 24/7, often 7200 or even 10k min^-1), expensive, usually twice as much as "run of the mill" of the same size - standard models (7200 or 5400 min^-1, occasionally inbetween) said to be specced for about 8/7, cheap, used to need ~10W, now usually ~6W - "green" models (mostly 5400, some 7200 min^-1) said to be specced for about 8/7, cheap, ~6W Basically, unless you shell out the money for server drives, don't look at names, look at the specs (e.g. cache size, MTBF) and the price ;) For me, "top" disk performance is irrelevant. The HD20[34][UW]I are supposed to do 130-160 MB/s (or more). Two runs of [lsscsi]: [1:0:0:0] disk ATA SAMSUNG HD204UI 1AQ1 /dev/sdb [3:0:0:0] disk ATA SAMSUNG HD203WI 1AN1 /dev/sdd # hdparm -t /dev/sdb /dev/sdd /dev/sdb: Timing buffered disk reads: 410 MB in 3.00 seconds = 136.54 MB/sec /dev/sdd: Timing buffered disk reads: 282 MB in 3.01 seconds = 93.60 MB/sec /dev/sdb: Timing buffered disk reads: 410 MB in 3.00 seconds = 136.66 MB/sec /dev/sdd: Timing buffered disk reads: 282 MB in 3.02 seconds = 93.46 MB/sec But that's misleading too: [lsscsi] [0:0:0:0] disk ATA SAMSUNG HD204UI 1AQ1 /dev/sda [4:0:0:0] disk ATA SAMSUNG HD203WI 1AN1 /dev/sde # hdparm -t /dev/sda /dev/sde /dev/sda: Timing buffered disk reads: 388 MB in 3.00 seconds = 129.30 MB/sec /dev/sde: Timing buffered disk reads: 332 MB in 3.02 seconds = 110.09 MB/sec /dev/sda: Timing buffered disk reads: 406 MB in 3.00 seconds = 135.13 MB/sec /dev/sde: Timing buffered disk reads: 226 MB in 3.01 seconds = 75.21 MB/sec But! In practice, with all the seeks and FS-Overhead and whatnot, I feel lucky if I get over 60MB/s while copying (big) files with mc, typical is something from 40 to 50 MB/s. With small files, it's much much lower anyway (I've got a ext3 only system and the disks tend to be full). So, all those "fancy" numbers you find in benchmarks are a datapoint, but in practice, I see little difference in speed over all my disks in this and the other box, even the 2 PATA 500G disks read/write about 40MB/s and there's little difference between the oldest and newest SATA disks. It is noticeable at times, when copying from a fast one to a fast one vs. slow to slow, but not very much. So, as stated before, it is not really relevant what brand/model you get. I've had bad experiences with IBM (DHEA and DTLA series, bought by Hitachi), Quantum (one 3.2G drive), Maxtor (various models from 9.1G to 80G, bought by Seagate), Seagate, WD, and Samsung, and weirdly enough, the worst were the 2 Samsungs that died a few days apart (both 500G IIRC -> cf. "twins" mentioned), where I lost quite a bit of (replaceable) stuff. One disk was just dead, it spun up IIRC, but not even the BIOS found it anymore, from the other, I was able to scrape most stuff off off it. Since then (and before for models from 2 x 160G to 3 or so 400G), the other Samsung drives have been reliable, and that's been a lot (20 or more I think). OTOH, out of 3 ST1500...AS Seagates, only 1 is still ok, 1 is decomissioned, the other is about to, due to losing sectors. The 1 WD20...EAR. SATA too. See my previous mail. OTOOH, other people have quite different experiences, e.g. Samsungs dying like flies and WD/Seagate rock solid. Whatever. And, with you being in Kolkata (right?), you'd have to check it out yourself anyway, as you got quite a different climate that Germany. Just think about heat and humidity (or are those drives in a air-conditioned environment?) Again: it does not really matter what brand/model of a e.g. 2T drive you get. If in doubt: get the cheapest (non-fake/-refurbished etc.). Think about "green"/5400 min^-1 as being a bit less snappy than 7200 min^-1 models, but needing less power and being cooler. Continuous transfer is IMO irrelevant, because if whether you don't get 130 MB/s or don't get 150 MB/s at the application level copying files with, say, 60 MB/s is irrelevant. For me, those "green" drives are fast enough, and as you can guess from what's in this box alone, moving (i.e. copy & delete) 100 GB about is routine ;) I don't care if moving 50GB (of big files, 200MB-2.xGB) takes 15 or 20 mins. I won't be sitting there watching it anyway. You want snappy? Get a SSD ;) One last datapoint: Samsung drives report running at lower temps than WD or Seagate (no idea about Hitachi). Not sure if they are cooler or just report cooler temps. HTH, -dnh -- Perl is the successful attempt to make a braindump executable. -- Lutz Donnerhacke -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse+owner@opensuse.org