Seagate’s first shingled hard drives now shipping: 8TB for just $260


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This is one thread that I haven't really been following too closely, so I'm not sure if anyone else has posted this.  But I just was checking out the Open Compute update at anandtech http://www.anandtech.com/show/9138/open-compute-hardware-tried-and-tested, and in one of the specifications (cold storage), they do make note of SMR drives  http://www.opencompute.org/assets/download/Open-Compute-Project-Cold-Storage-Specification-v0.5.pdf

 

To achieve low cost and high capacity, Shingled Magnetic Recording (SMR) hard disk

drives are used in the cold storage system. This kind of HDD is extremely sensitive to

vibration; so only 1 drive of the 15 on an Open Vault tray is able to spin at a given time

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You should be able to suspend some of the preclears to see if the others speed up. You can resume them when desired.

 

The syntax is "kill -STOP {pid}" to suspend, and "kill -CONT {pid}" to resume.

 

If you run "ps -ef|grep preclear" you should get the pids for the running preclears.

 

 

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Do I type that into a putty session as I am doing 6 preclears tty window things?

 

Not sure what you're saying here => if you've started these all in Telnet sessions, simply killing the Telnet session will also kill the pre-clear.

 

If you've started these in a Screen session, and switched between the windows with Alt-Fx, then you need to switch to the sessions you want to abort and do as noted above.

 

As I noted above, killing a couple of pre-clears will likely speed up the remaining ones.    I'm not sure just suspending them will have the same effect, as I don't know if that will release the resources (notably memory) that the suspended operations were using.

 

 

 

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I suspect if you kill another one you'll see a notable improvement in at least one more as well.  This is a pretty good indication the issue is simple resources -- with 8GB drives you apparently can't do more than 2-3 at once without some speed sacrifice due to available resources.

 

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=>  Are you using the most recent pre-clear script ?  [ http://lime-technology.com/forum/index.php?topic=2817.0 ]

 

=>  Your choices at this point are essentially to just wait it out;  or to abort ALL of the pre-clears, and then start 2 or 3 of them.  I think your problem is a resource issue.  I'd try just running 2 at a time --and if the speed looks okay after an hour or so perhaps start a 3rd.    Then just let those finish; and then repeat the process for your other drives.

 

 

 

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... actually, if you abort them all and start over, I'd just start ONE and wait 30 minutes or so to get a feel for the speed;  THEN start a 2nd and watch its speed after 30-60 minutes; and finally (if you want) start a 3rd to see if that impacts the speeds.  I would NOT try more than 3 at once.

 

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I now have 4 running but no speed change apart from the fast one which is now running at 76MB/s. I have now installed unmenu and its great to see the zeroing without pulling cables!

 

Maybe update to unraid v6?

 

Watching a gui during preclear is known to slow things down.

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165 to 180. The thing about this speed is that it's updating/refreshing very quickly. Unlike the server. It's is a over clocked i7 2600k though!!

 

I will let the server one run. They are all at 60%.

 

If that's 60% of the zeroing for the first cycle, you'd finish quicker by aborting and just running 2 at once, which would almost certainly give you FAR faster speeds.  You indicated you have these set for 3 cycles ... so at the slower speed that's going to take a VERY long time.  I'd abort; run 2 at once; and then run the last 2 at once after those have completed.  I suspect you'd finish quicker doing that than you will be waiting for them to complete at the current speeds.

 

 

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I tried stop the server but it froze at sync files after I clicked stopped. I looked at the activity lights on the hdds and one of the seagates was still active even though I cancelled all of the preclears. I then pulled the power and restarted my server and now it's parity checking. I am assuming it's not a good idea to do preclears now?

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The pre-clear is independent of server activity, so you could start one while the parity check is in progress.    But of course the system is using a lot more resources now than it would when it's idle, so the performance may not be as good as you like.

 

I'd just stop the parity check (you can run it later) and go ahead and get the pre-clears started.

 

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