February 5, 201115 yr I would like to swap out my current cache drive with another drive and then use the current cache drive as a data drive. Do I just: 01. Stop array. 02. Unassign cache drive. 03. Power down. 04. Replace current cache drive with smaller drive. 05. Insert current cache drive in free drive bay. 06. Power up. 07. Assign new smaller drive as cache. 08. Assign old cache drive as data drive. 09. Start array. I am running 4.7 with Default Partition Format set to 4K aligned. A. Is this the correct procedure to follow? B. Will parity still be valid? C. Will old cache drive, now data drive, need to be preclear and/or formatted? If so, it is not an advanced format drive, will I be OK?
February 5, 201115 yr OK, I give it a try, correct me if I'm wrong... A) Yes, looks good to me B) As far as I know is parity not longer valid, when adding a new drive. You should rebuild, at least that was the point when I added the last drive. C) Yes, preclearing and formatting is recommended. I always preclear drives before adding them, and when adding them to the array unRaid starts formatting, which takes only a few minutes. HTH, furymaster
February 5, 201115 yr A - Yes B - Yes C - I'm pretty sure unRAID will clear the drive when it is added. The server will not be available during this time. You can use the pre-clear script to do the pre-clear before you add it then the server will be available again immediately. The 4k setting works for any drive except jumpered EARS drives. The old setting only works for non-AF drives. Keep using the 4k setting. Peter
February 5, 201115 yr A - Yes B - Yes C - I'm pretty sure unRAID will clear the drive when it is added. The server will not be available during this time. You can use the pre-clear script to do the pre-clear before you add it then the server will be available again immediately. The 4k setting works for any drive except jumpered EARS drives. The old setting only works for non-AF drives. Keep using the 4k setting. Peter Since the cache drive already has a valid MBR, it will not be re-partitioned. It will be used as is, with a partition starting at sector 63. As mentioned, if you do not preclear the cache drive, then unRAID will clear it for you, but while it does the array will be off-line. For a 1TB drive it can take 4 or 5 hours. A 2TB drive will have the array offline 8 or 9 hours while unRAID clears the drive. I strongly suggest you preclear the disk before assigning it to the array. If you do, the array will be off-line for the few minutes you need to stop the array, assign the old cache drive to a data slot, and re-start the array. It is much easier if you have family members who have grown used to having the server available. I'll keep repeating this... No drive "needs" the new 4k-aligned setting. Some AF drives will perform better on small files ( < 4k) in tests, but you'll never notice it when using the drive in playing your media. If you do preclear the cache drive, and it is not a jumpered EARS drive, you can use the latest preclear_disk.sh program (ver 1.4 as of this post) and it will use the MBR un-aligned/MBR 4k-aligned setting you have chosen if you do not specify the "-A" or "-a" option on the command line. Joe L.
February 5, 201115 yr Author I will skip my step 8 and preclear the disk prior to assigning it to the array. It is a 2TB drive and I can't have the array being off-line that long. Since the old cache drive is not an AF drive, I will be using sector 63 option. I am a little confused on how unRAID would format this drive if I use the sector 63 option on preclear and have my Partition Format set at 4K - aligned? Also, what about the new cache drive? It too is not an AF drive. Should I preclear it too? I may just reset the Partition Format back to MBR - unaligned for this case since both drives are non-AF.
February 6, 201115 yr Since the old cache drive is not an AF drive, I will be using sector 63 option.It can use either. A disk partition that is aligned on a 4096 byte boundary is automatically also aligned on a 512 byte boundary. I am a little confused on how unRAID would format this drive if I use the sector 63 option on preclear and have my Partition Format set at 4K - aligned? If you use no option on the preclear_disk.sh script and invoke it like this: preclear_disk.sh /dev/sdX the preclear_disk.sh script will use the setting you've elected in the unRAID settings page. (as long as you use at least version 1.3 of the preclear script) If you selected MBR-unaligned it will create a pre-clear signature asking for a partition start on sector 63. If you selected MBR-4k-aligned, it will create a pre-clear signature asking for a partition start on sector 64. If you invoke the preclear script like this (using "-A" ): preclear_disk.sh -A /dev/sdX you will force a pre-clear signature asking for a partition start on sector 64 regardless of the setting in the unMENU settings screen. If you invoke the preclear script like this (using "-a" ): preclear_disk.sh -a /dev/sdX you will force a pre-clear signature asking for a partition start on sector 63 regardless of the setting in the unMENU settings screen. Also, what about the new cache drive? It too is not an AF drive. Should I preclear it too? You can.. it will burn it in and let you know of any potential problems before you start putting your data on it. I may just reset the Partition Format back to MBR - unaligned for this case since both drives are non-AF. As I said, it does not matter unless you do not specify a preference on the preclear_disk.sh command line by using the "-a' or "-A" options. You can format a non-AF drive as aligned at the 4096 byte boundary and it will work perfectly. I suggest you just leave the setting at MBR-4k-aligned. It only is used by unRAID if the disk has not been pre-cleared and does not already have an unRAID partition defined. Basically, it is used if unRAID does the clearing. Joe L. Just remember, once you partition a drive to start on sector 64, it will not be recognized as formatted on 4.6 unRAID or previous.
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