dlandon Posted February 27, 2022 Share Posted February 27, 2022 Unassigned Devices Preclear (UD Preclear) is an add on plugin to UD that allows you to manage preclearing disks either from the UD page or a separate page (Tools->Disk Utilities->Disk Preclear) meant to manage preclearing unassigned disks. This plugin is derived from the Preclear Disk Plugin authored by gfjardim. Disks that are candidates for preclearing will have a preclear icon next to the disk serial number in UD, and will be listed in the 'Tools->Disk Utilities->Settings->Disk Preclear' page. Only presenting unassigned disks that are eligible candidates for a preclear will prevent accidental data loss. You don't want to preclear a disk with data on it. For a disk to be considered a preclear candidate, it must have one of the following attributes: An Unassigned disk with no partitions. An Unassigned disk with a preclear signature and a partition with no file system. There are two methods available for preclearing: 'Enhanced' preclear written by gfjardim that supports pausing and resuming preclears. This is the recommended script to use. 'Docker' preclear is the preclear docker container authored by binhex using the latest version of the legacy preclear script. The advantage to using the docker container is that preclears are isolated to the docker container. This preclear script cannot be paused and resumed, and doesn't support notifications. The binhex preclear docker must be installed and running before this will show as a preclear choice. Both methods write a preclear signature that is accepted by Unraid. When a disk is precleared by UD Preclear, and subsequently installed in the array, Unraid will accept it as a cleared disk and not perform another lengthy clear operation. You do not have to pre-format the disk before adding it to the array. Unraid accepts a pre-cleared disk and will not do a clear when the disk in added if it sees the preclear signature. Preclears are done in the background so you don't have to leave any consoles open. The Tmux package is included so the preclears can run on background consoles. Please do not update the Tmux package through the NerdPack GUI. The latest version of Tmux has a bug and messes up the status display because the terminal size is defaulted to 24x80 and can't be changed. If you want to format the disk for use in UD or as a Pool device, click the red 'X' next to the preclear status line to remove the Preclear Log, then click the red 'X' next to the serial number to remove the preclear signature and all partitions. You'll then be able to format the disk. The choices for preclear operations are: Clear Disk - The disk is cleared and the Unraid signature is written to the disk. This will create an empty partition on the disk. Erase Disk - Erase the entire disk by writing all zeros. The preclear signature is removed. Erase and Clear Disk - random patterns are written to the disk and then zeroes are written. This is a good choice for a disk to be discard to ensure all traces of files are removed. Verify Signature - The disk signature is checked. Verify Disk - The disk signature is checked and the disk is verified to be zeroed. Post-read Verify - Perform a post read verify to check the disk. This is not available in the 'Enhanced' script. Clear Signature - Remove the preclear signature from the disk. This is not available in the 'Enhanced' script. You can follow the status of preclears in UD, on the UD Preclear page, or by hovering your mouse on the preclear icon in the Unraid footer. While preclearing disks is not necessary with the current Unraid versions, users get a sense of confidence with pre-testing their disks. When the original preclear script was written, Unraid would take the array off line while it cleared a disk if it was not precleared. That's why the script is called 'preclear'. In the old days, preclearing a disk would prepare it for the array and Unraid would not take the array offline when a new disk was added. UD Preclear is a direct replacement for the Preclear Disk Plugin. You will have to remove that plugin before the UD Preclear can be installed. UD must be installed before UD Preclear will install. Go to 'Apps' and search for Unassigned Devices Preclear and install it from there. UD+ is not necessary for preclearing, although you'll need it to delete partitions and format disks. Because UD Preclear uses some features in Unraid starting with 6.9, it is not backwards compatible with any Unraid version older than 6.9. 5 2 Quote Link to comment
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