July 17, 201114 yr Hello, I am a user of preclear so I understand some aspects of it. I will briefly explain what my situation is. Previous Setup ***NOTE NEVER PRECLEARED*** 3x500GB --- WD Drives -1x500GB AADS (GREEN) -2x500GB AAKS -jumperless 1xparity 500GB (being replaced) ************************* These hard drives in question have had all their data backed up and are moving into a new hardware environment (motherboard/ram/cpu/case) Right now I have the new WD 2TB EARS (GREEN) preclearing with : preclear_disk.sh -A /dev/sda (which is the string i ALWAYS run on any of my new WD 2TB GREENS -EARS) my question is regarding the other data drives I want to preclear / format what would the preclear string be??? I thought this would work: preclear_disk.sh -z -n /dev/sda -n = fast preclear -z = formatting the drive for UNRAID but it does not like that string.... any suggestions? as well, how do I go about clearing my UNRAID USB FLASH DRIVE of all the old history or start a fresh unraid key .... make a new .dat file?? any suggestions appreciated, thank you
July 17, 201114 yr -n = write zeros to the drive only. Write a pre-clear signature to the MBR when done. You are in a hurry... Do not bother to check for un-readable sectors, you feel lucky, and would rather learn of any un-readable sectors AFTER you load the disks with your files... when you attempt to read them off the disk or perform the first parity calculation. Do not verify the zeros you wrote actually can be read back successfully... odds are in your favor it will work..., not 100% certain, but somewhere close. :'( -z = write zeros to the first 512 bytes of the disk, erasing anything in the master-boot-record. (including any pre-clear signature or partition table that might be in the MBR currently) The rest of the disk is left unchanged.
July 17, 201114 yr Author -n = write zeros to the drive only. Write a pre-clear signature to the MBR when done. You are in a hurry... Do not bother to check for un-readable sectors, you feel lucky, and would rather learn of any un-readable sectors AFTER you load the disks with your files... when you attempt to read them off the disk or perform the first parity calculation. Do not verify the zeros you wrote actually can be read back successfully... odds are in your favor it will work..., not 100% certain, but somewhere close. :'( -z = write zeros to the first 512 bytes of the disk, erasing anything in the master-boot-record. (including any pre-clear signature or partition table that might be in the MBR currently) The rest of the disk is left unchanged. so what string do I use for these data drives ? and yes I am in a hurry to be honest --- basically want to do a quick preclear on these drives --- completely clear. *EDIT*as well I want to delete history on my unraid key... where it stands now it still sees the missing drives. I want it to have my old configuration deleted from the key.... *I renamed disk.cfg and super.dat --- seemed to fix the problem* should i run 2 instances of preclear?? preclear_disk.sh -z /dev/sda then preclear_disk.sh -n /dev/sda the add to the array?
July 17, 201114 yr -n = write zeros to the drive only. Write a pre-clear signature to the MBR when done. You are in a hurry... Do not bother to check for un-readable sectors, you feel lucky, and would rather learn of any un-readable sectors AFTER you load the disks with your files... when you attempt to read them off the disk or perform the first parity calculation. Do not verify the zeros you wrote actually can be read back successfully... odds are in your favor it will work..., not 100% certain, but somewhere close. :'( -z = write zeros to the first 512 bytes of the disk, erasing anything in the master-boot-record. (including any pre-clear signature or partition table that might be in the MBR currently) The rest of the disk is left unchanged. so what string do I use for these data drives ? and yes I am in a hurry to be honest --- basically want to do a quick preclear on these drives --- completely clear. The quickest that verifies is preclear_disk.sh -W /dev/sdX Since un-readable sectors are then detected in the post-read phase, they will not actually be re-allocated until the disk is written. slightly faster, but without a verification would be to use "dd" to read the entire drive dd if=/dev/sdX of=/dev/null bs=1M followed, after it finishes, by preclear_disk.sh -n /dev/sdX to write it. as well I want to delete history on my unraid key... where it stands now it still sees the missing drives. I want it to have nothing in that list... un-assign all the drives, then Use the initconfig command to set a new initial disk configuration.
July 17, 201114 yr Author ran initconfig, worked well.... going to run preclear on drives now. -W first then -n thank you for the help
July 17, 201114 yr ran initconfig, worked well.... going to run preclear on drives now. -W first then -n thank you for the help -W writes zeros, then reads them back to verify. It skips the pre-read that would allow the identification of un-readable sectors BEFORE the writing of zeros that would allow the SMART firmware on the disk to re-allocate them. Instead, just leave off the extra options, and accept that I have more experience at the pre-clear process than you. -W followed by -n will take the same amount of time as no options at all, and not be as effective. You apparently care more about your time than your data. It is OK, just cross your fingers... in my personal experience about 1 in 10 new drives has been defective in some way. I've only had to RMA two brand new drives so far. Joe L.
July 17, 201114 yr Author Thanks Joe, and yes I do believe you have a lot more experience I don't doubt you. It's really nice you responded so prompt! So much thanks ! The time thing is a friend brought his server to me from out of town, I told him I needed a week, but its being rushed to 2-3 days if that... I only have time to preclear one 500GB and his other 2 will not be. I just told him when you swap out the 500's for 2TB in future to preclear them then, and add to array. Thank you for all the help, I have now got a better grasp on this process as we have talked tonight. learning as I encounter new situations All the best !!
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