I am pre clearing 1 3tb drive.  The first step seemed normal over 100 mb a sec.  Step 2 is a whole different beast.  I am only getting 13mb a sec.  It has been clearing for close to 24hr and it is only 23% done.  I am including a copy of my syslog.  Can you please let me know if you see something out of the norm.  The drive is connected to the mobo sata controller and set to AHCI.  I am not sure if I still have a setting wrong in the bios because from my reading if unraid identifys the drive as /dev/hd* it thinks it is an ide drive.  In this case it identifies it as /dev/hdc.

 

Thanks for any help.

syslog_2.zip

I am pre clearing 1 3tb drive.  The first step seemed normal over 100 mb a sec.  Step 2 is a whole different beast.  I am only getting 13mb a sec.  It has been clearing for close to 24hr and it is only 23% done.  I am including a copy of my syslog.  Can you please let me know if you see something out of the norm.  The drive is connected to the mobo sata controller and set to AHCI.  I am not sure if I still have a setting wrong in the bios because from my reading if unraid identifys the drive as /dev/hd* it thinks it is an ide drive.  In this case it identifies it as /dev/hdc.

 

Thanks for any help.

Yes, you have a BIOS setting wrong.  The disk controller for that sATA port  is in a "legacy" mode that treats the drive as if it an old IDE drive.  This is almost always slower, sometimes a LOT slower.  This mode is typically the default since older Microsoft operating systems had no SATA drivers.  If this mode dis not exist, windows XP and prior could not boot on that motherboard.

 

You want the disk controller to be in AHCI mode and NOT in a legacy mode.  This will take advantage of the higher speed SATA communications protocol.

 

Changing the setting will not cause any loss of data.  It will just work faster.  Obviously, you cannot change it while preclearing, so... your choice when to correct it.  It will not affect the data on the drive or the pre-clear signature.

 

Joe L.

I am using unraid 5 rc12.  Do I need to use the -A option when preclearing the disk.  I went ahead and stopped the preclear and made the adjustments to the bios.

 

Thanks

That option is ignored for drives larger than 2TB.

 

You mention you are running 5.0 RC12a?  I would suggest upgrading to the 5.0 RC16c release before continuing.  You want to make sure that you have no issues on your system with this release as it is looking increasingly likely that the 5.0 final will not be much changed from RC16c.

That option is ignored for drives larger than 2TB.

 

You mention you are running 5.0 RC12a?  I would suggest upgrading to the 5.0 RC16c release before continuing.  You want to make sure that you have no issues on your system with this release as it is looking increasingly likely that the 5.0 final will not be much changed from RC16c.

 

I agree  it's a good idea to update to RC16c ... but this has NOTHING to do with the pre-clear.  The pre-clear script is simply a Linux script and runs entirely "outside" of UnRAID.