immense delayed write to file system (ZFS and UFS2), performance issues

Oliver Lehmann lehmann at ans-netz.de
Tue Jan 19 18:57:26 UTC 2010


Hi,

it seems that I'm not experiencing this at all...

Jeremy Chadwick wrote:

> WD10EACS   - WD Caviar Green,   1TB, 16MB, variable rpm

have one (external HDD, "always" powered on)
Model = WDC WD10EAVS-00D7B1
Firmware Version = 01.01A01
Power_On_Hours		5757
Power_Cycle_Count	75
Load_Cycle_Count	127

> WD10EADS   - WD Caviar Green,   1TB, 32MB, variable rpm

have four, got them in Sep/09.
one is RMAed right now because it had defective sectors in Dec/09 (surprisingly
the first WDC I encountered problems so far).
All four are used as a RAID-5 configured with my 3ware 9500-4LP. I don't know
if the controller requests data from the drives in a very short period of time.
I'm MRTGing some SMART attributes which should at least query the drive every
minute. The ata idle feature is not supported at all trough the 3ware
controllers.

For the remaining 3 drives:
Model = WDC WD10EADS-00L5B1
Firmware Version = 01.01A01
Power_On_Hours		2538
Power_Cycle_Count	140
Load_Cycle_Count	141
Power_On_Hours		2526
Power_Cycle_Count	133
Load_Cycle_Count	134
Power_On_Hours		2490
Power_Cycle_Count	126
Load_Cycle_Count	128

So - I'm not experiencing this problem at all but I "feel" that the
drives are reacting more slowly than my previous WD2500KS-00MJB0 are.
changing a directory and then typing ls takes some time until the result
is displayed... I can live with that but it doesn't feel "good"
And - it is not really something I would call "fast" - but it saves
power :)

The 3ware RAID-5 over 4 disks (using the EAVS from above as replacement
right now until WDC sends a new drive back):
Version  1.96       ------Sequential Output------ --Sequential Input- --Random-
Concurrency   1     -Per Chr- --Block-- -Rewrite- -Per Chr- --Block-- --Seeks--
Machine        Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP  /sec %CP
nudel.salatschue 6G    89  99 76321  38 29285  21   249  99 111225  33 201.7  13
Latency               106ms     247ms    1155ms   63744us     145ms     382ms
Version  1.96       ------Sequential Create------ --------Random Create--------
nudel.salatschuesse -Create-- --Read--- -Delete-- -Create-- --Read--- -Delete--
              files  /sec %CP  /sec %CP  /sec %CP  /sec %CP  /sec %CP  /sec %CP
                 16   571   6 +++++ +++  1095   8   617   6 +++++ +++   611   5
Latency               523ms      61us     125ms     103ms      87us     159ms



-- 
 Oliver Lehmann
  http://www.pofo.de/
  http://wishlist.ans-netz.de/


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