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

[Erik Stian Tefre]

Morgan Wesström wrote:
> Garrett Moore wrote:
>> The drives being discussed in my related thread (regarding poor performance)
>> are all WD Green drives. I have used wdidle3 to set all of my drive timeouts
>> to 5 minutes. I'll see what sort of difference this makes for performance.
>>
>> Even if it makes no difference to performance, thank you for pointing it out
>> -- my drives have less than 2,000 hours on them and were all over 90,000
>> load cycles due to this moronic factory setting. Since changing the timeout,
>> they haven't parked (which is what I would expect).
>>
> 
> You're welcome. I just feel as bad for you as for everyone else who has
> bought these obviously Windoze optimized harddrives. Unfortunately
> neither wdidle3 nor an updated firmware is available or functioning on
> the latest models in the Green series. At least that's what I've read
> from other people having this issue. WD only claims they don't support
> Linux and they probably have never heard of FreeBSD.
> 
> If anyone successfully has fixed their WD15EADS drives this way I'd be
> interested in hearing from you. One of my drives has 216,000 load cycles
> accumulated over 8 months. That's one every 2nd minute... and I was hit
> by the Seagate 7200.11 fiasco too. Running on Samsungs now :-)

Keeping this python script running prevents Load_Cycle_Count from
incrementing on my WD15EADS drives by forcing a write every 5 seconds (2
drive zfs mirror pool, average of 2 load cycles per minute when the
script is not running):

import time,os

mypool = "/zfspool"
#         ^^ Change to your pool!

fname = os.path.join(mypool, "wd_green_anti_idle.pyfile")
c = 0
f = open(fname, "w")

while True:
        if c == 100:
                f.close()
                f = open(fname, "w")
                c = 0
        c += 1
        time.sleep(5)
        f.write("a")
        f.flush()
        os.fsync(f.fileno())


--
Erik