WD Caviar Green drives in Linux
Moderators: NeilBlanchard, Ralf Hutter, sthayashi, Lawrence Lee
WD Caviar Green drives in Linux
Hi,
I have recently bought 1.5 TB Caviar Green drive (the new version with 64MB of Cache) and all the problems started First I noticed that the performance of this drive was shockingly bad (worse than 5 year old USB stick). After loads of searching and asking questions I found out that in order to get reasonable performance you need to align your partitions to the physical 4kb sectors on the drive.
The correct way to align partitions is here: http://www.linuxconfig.org/linux-wd-ear ... ced-format
And this article gives a pretty good benchmark so that you can check if your partition table is correct: http://article.gmane.org/gmane.linux.ut ... ux-ng/2955
On top of this the problem that the drive constantly parks and unparks the heads still exists (despite a note in the official SPCR review), and the users need to change the timeout setting using the tool provided by WD:
http://wdc.custhelp.com/cgi-bin/wdc.cfg ... _topview=1
So to sum up, I spent so much time getting this thing to work that I think its fair to say that these drives are virtually incompatible with Linux. I am not sure about alternatives, but I am sure there are some.
I have recently bought 1.5 TB Caviar Green drive (the new version with 64MB of Cache) and all the problems started First I noticed that the performance of this drive was shockingly bad (worse than 5 year old USB stick). After loads of searching and asking questions I found out that in order to get reasonable performance you need to align your partitions to the physical 4kb sectors on the drive.
The correct way to align partitions is here: http://www.linuxconfig.org/linux-wd-ear ... ced-format
And this article gives a pretty good benchmark so that you can check if your partition table is correct: http://article.gmane.org/gmane.linux.ut ... ux-ng/2955
On top of this the problem that the drive constantly parks and unparks the heads still exists (despite a note in the official SPCR review), and the users need to change the timeout setting using the tool provided by WD:
http://wdc.custhelp.com/cgi-bin/wdc.cfg ... _topview=1
So to sum up, I spent so much time getting this thing to work that I think its fair to say that these drives are virtually incompatible with Linux. I am not sure about alternatives, but I am sure there are some.
I have one wd20eads running ubuntu 10.04. Thre is no reason (other than getting annoyed by partitioning problems) to purchase an ears model at this time. My eads does not park the heads so much:
Code: Select all
9 Power_On_Hours 0x0032 100 100 000 Old_age Always - 428
10 Spin_Retry_Count 0x0032 100 253 000 Old_age Always - 0
11 Calibration_Retry_Count 0x0032 100 253 000 Old_age Always - 0
12 Power_Cycle_Count 0x0032 100 100 000 Old_age Always - 9
192 Power-Off_Retract_Count 0x0032 200 200 000 Old_age Always - 3
193 Load_Cycle_Count 0x0032 200 200 000 Old_age Always - 875
-
- Posts: 450
- Joined: Mon Mar 29, 2010 2:47 am
- Location: Bratislava, Slovak Republic
@fjf: No reason ? Well, there is one very good reason - some shops or even countries don't have EADS series anymore (for example you can't find them in my country).
And just for info, neither does my WD20EARS park much (with one hour spindown time):
And just for info, neither does my WD20EARS park much (with one hour spindown time):
Code: Select all
ID# ATTRIBUTE_NAME FLAG VALUE WORST THRESH TYPE UPDATED WHEN_FAILED RAW_VALUE
4 Start_Stop_Count 0x0032 100 100 000 Old_age Always - 165
9 Power_On_Hours 0x0032 098 098 000 Old_age Always - 2165
12 Power_Cycle_Count 0x0032 100 100 000 Old_age Always - 25
192 Power-Off_Retract_Count 0x0032 200 200 000 Old_age Always - 13
193 Load_Cycle_Count 0x0032 200 200 000 Old_age Always - 434
-
- Posts: 450
- Joined: Mon Mar 29, 2010 2:47 am
- Location: Bratislava, Slovak Republic
I should have included more details, sorry. I have WD15EARS. The load cycle count after 4 months of usage:
193 Load_Cycle_Count 0x0032 185 185 000 Old_age Always - 45122
The 4kb sectors DO cause issues in Linux, because the drive reports 512b sector size. So if your partitioning program doesn't align the partitions with 4kb real sector boundary, the disk internally will do more drive access then necessary.
193 Load_Cycle_Count 0x0032 185 185 000 Old_age Always - 45122
The 4kb sectors DO cause issues in Linux, because the drive reports 512b sector size. So if your partitioning program doesn't align the partitions with 4kb real sector boundary, the disk internally will do more drive access then necessary.
-
- Posts: 450
- Joined: Mon Mar 29, 2010 2:47 am
- Location: Bratislava, Slovak Republic
Well, i used Arch linux, where you partition your hard drive manually (and i alligned them to sector 2048 to be safe).
Code: Select all
[root@filebox ~]# fdisk -lu /dev/sde
Disk /dev/sde: 2000.4 GB, 2000398934016 bytes
81 heads, 63 sectors/track, 765633 cylinders, total 3907029168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000
Device Boot Start End Blocks Id System
/dev/sde1 2048 3907029167 1953513560 83 Linux
[root@filebox ~]# fdisk -lu /dev/sdc
Disk /dev/sdc: 2000.4 GB, 2000398934016 bytes
81 heads, 63 sectors/track, 765633 cylinders, total 3907029168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000
Device Boot Start End Blocks Id System
/dev/sdc1 2048 3907029167 1953513560 83 Linux
Why not align to 64? As I understand it, you have to do it to a number divisible by 8, no? Also, can you post a link to the procedure you used to partition the drive?faugusztin wrote:Well, i used Arch linux, where you partition your hard drive manually (and i alligned them to sector 2048 to be safe).
Can you run smartctl -a /dev/sdX and post the output? I'm curious about the number of load_cycle_counts per total power on hours for you. I too have an Arch server and will be installing an EARS drive on it soon.
Thanks!
-
- Posts: 450
- Joined: Mon Mar 29, 2010 2:47 am
- Location: Bratislava, Slovak Republic
http://thunk.org/tytso/blog/2009/02/20/ ... lock-size/
That was one of the first results to "fdisk 4k align" google search, i never seen gandrusz's links before he posted them, but i knew beforehand that i must align the drives (i have few SSD's, so align problem was known to me).
And smartctl - look 5 posts above yours .
I used the "hdparm -S 242 /dev/sdc" command to set a 1 hour spindown time, plus since some drives i have in file server doesn't support hdparm -S at all, i also installed the hd-idle utility which makes the drives spin down via hdparm -y command (which allways works).
Code: Select all
fdisk -H 224 -S 56 /dev/sdb
And smartctl - look 5 posts above yours .
Code: Select all
9 Power_On_Hours 0x0032 100 100 000 Old_age Always - 428
193 Load_Cycle_Count 0x0032 200 200 000 Old_age Always - 875
Thanks for the hdparm -S 244 suggestion. I just installed my wd20ears and found that the lcc was counting up. 23 in a few min. That command halts this retarded behavior. Do you add it to your /etc/rc.local or something to fix it at boot? My understanding is that the hdparm commands do not survive a reboot.
-
- Posts: 450
- Joined: Mon Mar 29, 2010 2:47 am
- Location: Bratislava, Slovak Republic
-
- Posts: 15
- Joined: Sun Aug 08, 2010 6:02 am
- Location: cz
Re:
Don´t be so sure. All of Caviar Green drives I had did not report any problem with load_cycle_count. But. All of them produced very silent "click-click sound" every 8 seconds. After using wdidle utility, that quiet sound disappeared. I guess WD solve the load_cycle_count problem by very ugly hack. They just crippled SMART table not to count real load and unload cycles. The bound that value with power on/off state thus the only time +1 is added to load_cycle_count is when drive is powered off and on.fjf wrote:I have one wd20eads running ubuntu 10.04. Thre is no reason (other than getting annoyed by partitioning problems) to purchase an ears model at this time. My eads does not park the heads so much:
I would not trust Caviar Green line anymore!