Preclear hard drive question

[TBSCamCity]

My unraid server is currently full with 12 hard drives (only has 12 hot swap bays). I just bought 6 8TB hard drives and would like to pre-clear them before beginning to swap out the drives. How do you guys go about preclearing when you have a full server? Do you guys have another server with free slots for preclearing? Or is there a way I can swap one drive at a time, for example, and preclear the drive before rebuilding the array? Any input would be greatly appreciated thanks.

[landS]

Not tried myself.... But what about a USB 3.0 to HDD dock? 

[TBSCamCity]

1 hour ago, landS said:

Not tried myself.... But what about a USB 3.0 to HDD dock? 

Ah I think I have one of those lying around somewhere... I hadn't even thought of that. Thanks I'll try that way when I get home this weekend.

[SSD]

Don't suggest preclearing in a hot little enclosure. Almost any computer can boot up a trial stick and run a preclear. Although not recommended for active environments, I have run a power and sata cable out the back of a computer and flipped the drive on its bask (label side down) to preclear a drive. Running a small fan is helpful to keep the drive cool.

[TBSCamCity]

7 minutes ago, bjp999 said:

Don't suggest preclearing in a hot little enclosure. Almost any computer can boot up a trial stick and run a preclear. Although not recommended for active environments, I have run a power and sata cable out the back of a computer and flipped the drive on its bask (label side down) to preclear a drive. Running a small fan is helpful to keep the drive cool.

Good point. I thought about doing the same thing but since my rack is full and there isn't anyway for me to pull out the server without turning it off I may just repurpose another server I have for preclears. Thanks for the input.

[c3]

Since I buy plenty of the external enclosure drives, using USB to test/preclearing eases the risk of shucking a DOA/early failure drive. It is much slower, but often the testing finishes long before I get time to get back to work on them. Weekdays can be hard to get time for home projects.

 

So I use USB, but not because no slots/bays, just to get some testing before breaking plastic

 

The convection cooling is not what you really want, even on the bare drive. I do add a bit of forced air cooling, as everyone has said. Mine is cut cardboard boxes, and wonderful blue tape.

Edited April 17, 2017 by c3

[BRiT]

I'm preclearing the Seagate 8TB External USB3 drives via a USB3.1 controller card. It's not that much slower at all. As @c3 indicates, the preclear typically finishes before I have enough free time to move onto the next step. Though if you can, try preclearing the drives connected internally. But it's not the end of the world if you have to do so externally via USB3.

 

A single preclear cycle on the 8TB Archive drive is around 45 hours when it's in the external enclosure. That's fast enough for me. The drive does get much warmer in the enclosure, hitting 48 C at the highest instead of remaining in the 30s C when run internally.

 

Here's the first preclear results.

 

#   Step 1 of 5 - Pre-read verification:                                                  [14:46:14 @ 150 MB/s] SUCCESS    #
#   Step 2 of 5 - Zeroing the disk:                                                       [14:39:48 @ 151 MB/s] SUCCESS    #
#   Step 3 of 5 - Writing unRAID's Preclear signature:                                                          SUCCESS    #
#   Step 4 of 5 - Verifying unRAID's Preclear signature:                                                        SUCCESS    #
#   Step 5 of 5 - Post-Read verification:                                                 [16:29:27 @ 134 MB/s] SUCCESS    #

 

#   190-Airflow_Temperature_Cel  23       48       Up 25                                                                   #