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Need to replace 1 drive (4 content 2 parity)

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L'rak Kazz
2017-02-15
2017-02-15
  • L'rak Kazz

    L'rak Kazz - 2017-02-15

    I have a drive that is "acting up" - but functional. Here is my setup
    d1 - 5tb
    d2 - 4tb <-- this one is acting up
    d3 - 4tb
    d5 - 5tb
    p1 - 8tb (partitioned to 6tb parity + 2 tb livedata {not protected by snapraid})
    p2 - 8tb (partitioned to 6tb parity + 2 tb livedata2 {not protected by snapraid})

    Goal:
    I want to swap out d2 and replace it with an 8tb drive

    Questions:
    1) I know I have to adjust my parity drives from 6tb to 8tb by removing livedata partitions. If I resize these partitions and make those drives 8tb instead of 6+2, will I need to force a sync to recreate parity? Or will it be ok because the parity drive never ran out of space?
    2) Should I remove d2-4tb and make d2-8th with same uuid (so snapraid doesnt complain about uuid) and do a snapraid fix to repopulate the drive? I figure any type of copy to repopulate d2 will have the bottleneck of write speed of the drive itself be it DD or snapraid fix
    3) Does changing the drive size (of d2) require snapraid to need a forced sync of the parity drives because the geometry of the array snapraid is handling has changed?

     
  • Leifi Plomeros

    Leifi Plomeros - 2017-02-15
    1. No need to repartition the parity disks until you get close to 6 TB actual data on the new d2. So right now, just focus on replacing the disk and deal with the parity disks later.
    2. Snapraid won't complain (only warn you) about UUID when you change a single drive. Recommendation is to try copying manually first and if that doesn't work use fix instead. If you don't have enough drive bays or sata ports then temporary disconnect one of the parity disks and use that drivebay while manually copying the old files.
    3. No, the maping between files and parity blocks is based on the files themself, not the physical location of the files.

    Step by step instruction:
    1. Connect the new drive.
    2. Partition and format new drive as 8 TB
    3. Update config so that d2 is pointed at the new disk (same for any content file on d2)
    4. Manually copy everything from old drive to new drive
    5. If manual copy failed use snapraid fix -d d2 -l logfile.txt to restore the files to the new disk
    6. Remove the old d2 disk (and put back the parity disk if you had to remove it)
    7. Run snapraid status and snapraid diff to check that everything seems OK (warning message about UUID for d2 is OK, lots of removed files is not).
    8. Run snapraid sync (only takes a few seconds to update UUID)
    9. Optionally run snapraid scrub -p 100 -o 0 to make sure that no silent corruption has been introduced in the files of new d2 (check -d d2 could be used instead if you prefer to only verify d2 and nothing else).
    10. Avoid filling d2 with more than 6 TB data until you have room for larger parity files.

    When the big day comes to increase room for parity files, if you are lucky they are located on the first partition. In that case just remove the second partition and increase the size of partition. Done.

    If not lucky (and don't have a spare 8 TB disk): Remove both partitions from one of the parity disks, use snapraid fix to restore the parity. Repeat for the next parity disk.

     

    Last edit: Leifi Plomeros 2017-02-15
  • L'rak Kazz

    L'rak Kazz - 2017-02-15

    Good stuff - thank you

     

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