SpaceInvaderOne Posted January 28, 2017 Share Posted January 28, 2017 Hi guys this week i have made a tutorial about how to add a cache drive to your server. It also shows how to upgrade or replace an existing cache drive without loosing data Also you will see how to create a raided btrfs cache pool. Hope you find it useful! How to add a cache drive, replace a cache drive or create a cache pool 4 1 Quote Link to comment
RobJ Posted January 28, 2017 Share Posted January 28, 2017 More outstanding work! I've added it to Guides and Videos. Also added a plug, for the credit deserved! Quote Link to comment
1812 Posted January 29, 2017 Share Posted January 29, 2017 stupid question time: when swapping out a cache drive, could you not have just changed the share setting from prefer to yes, and then invoked the mover to send them back to the array, then after swapping out the drive, reversed the process? Or does that eat the files? Quote Link to comment
John_M Posted January 29, 2017 Share Posted January 29, 2017 stupid question time: when swapping out a cache drive, could you not have just changed the share setting from prefer to yes, and then invoked the mover to send them back to the array, then after swapping out the drive, reversed the process? Or does that eat the files? Do you mean like this? Quote Link to comment
1812 Posted January 29, 2017 Share Posted January 29, 2017 stupid question time: when swapping out a cache drive, could you not have just changed the share setting from prefer to yes, and then invoked the mover to send them back to the array, then after swapping out the drive, reversed the process? Or does that eat the files? Do you mean like this? bingo. Quote Link to comment
SpaceInvaderOne Posted January 29, 2017 Author Share Posted January 29, 2017 stupid question time: when swapping out a cache drive, could you not have just changed the share setting from prefer to yes, and then invoked the mover to send them back to the array, then after swapping out the drive, reversed the process? Or does that eat the files? Do you mean like this? bingo. Yes, its fine to set shares to use cache "yes" then let mover move them then set share setting back. Its the official way and probably easier to set the cache to yes and use mover. The way I use in my video is just my personal preference and the way I do it personally. My reasons I don't use mover for that part is as follows 1. Mover will move data from the cache to the array not just copy it. So old cache will be blank afterwards. I prefer to copy the data manually so the data remains on the old cache as well and isn't removed. Yes, it's a little more effort to manually copy each share. Its worth it to me, just in case anything goes wrong during the process I have the original cache drive intact and is a "backup". For example, in the past, I have had an SSD fail after a few days, so that makes me cautious. So I like to keep my old cache for a bit then if the new SSD cache should fail then I can just pop the old one back in. (Also mover will only move data that is in a share. Sometimes it is possible a user may have data on the cache that isn't part of a share (although unlikely for most people)) 2. Mover doesn't give an estimated time to complete as no progress bar. I like to work through it manually and I have a good idea of how long there is left to complete it. The disadvantage of my method is you can't just leave it and go away. Ie let it run overnight Like I said this is just how I do this when upgrading to a larger cache drive but either method will give the desired result Quote Link to comment
1812 Posted January 29, 2017 Share Posted January 29, 2017 it's still quite important to know how the app data backup works, and to be using it. I asked my question from an honest point of not knowing if there was an issue that i didn't know about using mover. I was also thinking this morning that previously, i've just copied the entire contents of the cache using Kruasder to the array temporarily then move back and hadn't had the issues with docker images that I guess some others have had. I think there are multiple ways to do it. And you've outlined several reasons for that. Some are safer for data storage than others. Quote Link to comment
John_M Posted January 29, 2017 Share Posted January 29, 2017 You need to stop all dockers and the docker service so that the image is unmounted before moving the docker.img file. Similarly, VMs and the VM service need to be stopped. It's safe to move appdata once dockers are stopped. It doesn't matter whether you copy or move, either manually or with the Mover, though gridrunner makes a valid point about keeping the old files on the old cache disk as a backup. Quote Link to comment
SpaceInvaderOne Posted January 29, 2017 Author Share Posted January 29, 2017 You need to stop all dockers and the docker service so that the image is unmounted before moving the docker.img file. Similarly, VMs and the VM service need to be stopped. It's safe to move appdata once dockers are stopped. It doesn't matter whether you copy or move, either manually or with the Mover, though gridrunner makes a valid point about keeping the old files on the old cache disk as a backup. Exactly thats why trying to copy the docker image with krusader is not good. Because krusader is a docker then docker image is mounted and in use. CA Appdata Backup / Restore works by shutting down the all running dockers and then copying all the appdata (unless you have excluded some folders) then restarts the dockers afterwards. Quote Link to comment
_0m0t3ur Posted April 29, 2018 Share Posted April 29, 2018 I am building my server now. I appreciate these videos, which will make the deployment of my hardware much easier. Thank you. 1 Quote Link to comment
Phatty Posted May 10, 2021 Share Posted May 10, 2021 Hi Team Silly question but I assume things have changed since 2017, I am trying to follow the instructions on here but I do not see "Cache Devices" section but I do see pool, has the terminology changed? Even this page refers me here, a little confusing https://wiki.unraid.net/Cache_disk#Cache_settings Quote Link to comment
itimpi Posted May 10, 2021 Share Posted May 10, 2021 25 minutes ago, Phatty said: Hi Team Silly question but I assume things have changed since 2017, I am trying to follow the instructions on here but I do not see "Cache Devices" section but I do see pool, has the terminology changed? Even this page refers me here, a little confusing https://wiki.unraid.net/Cache_disk#Cache_settings Yes. Starting with Unraid 6.9.0 you can now have multiple 'pools', any of which can (optionally) act as a cache for nominated shares and whose names are user defined. Depending on context 'cache' and 'pool' can frequently be considered as interchangeable terms. Online documentation is steadily being updated to use 'pool' instead of 'cache' where appropriate. Quote Link to comment
Phatty Posted May 10, 2021 Share Posted May 10, 2021 Great! thanks for clarifying. Quote Link to comment
Glonch Posted June 11, 2021 Share Posted June 11, 2021 With all the changes to cache/pools... Question: I have a cache with 3 drives in RAID 0... I'd like to replace it with a slightly smaller single drive (1.5 TB to 1TB... only using 12% of the cache at the moment). After looking around, there are so many dated and conflicting articles/videos on how to accomplish this. Any help would be greatly appreciated. Thanks Quote Link to comment
dopeytree Posted August 25, 2022 Share Posted August 25, 2022 (edited) Love the videos but do wish the unraid wiki was up to date... Folks have to watch a 19min video to see all the topics until reach the bit relevant to them. Perhaps @SpaceInvaderOne could use timelinks in the descriptions. Although this means less complete video plays & perhaps less ad revenue... You can't beat written instructions! This entry is old and doesn't mention how to replace a cache drive https://wiki.unraid.net/Cache_disk and this Entry is blank... https://wiki.unraid.net/Replace_A_Cache_Drive Is the wiki controlled by unraid, perhaps it need some community involvement? Edited August 25, 2022 by dopeytree Quote Link to comment
itimpi Posted August 25, 2022 Share Posted August 25, 2022 4 minutes ago, dopeytree said: Is the wiki controlled by unraid, perhaps it need some community involvement? All the "Official" documentation is on links that start with https://wiki.unraid.net/Manual/ (and this is what the 'Manual' link at the bottom of the GUI takes you to). Anything else is community contributed content. Quote Link to comment
dopeytree Posted August 25, 2022 Share Posted August 25, 2022 Thanks - https://wiki.unraid.net/Manual/Storage_Management#Cache Quote Link to comment
Bushibot Posted October 1, 2023 Share Posted October 1, 2023 I feel like this is dumb question but... my cache drives are setup as ZFS mirrored. I have one drive in the pool that I think is having issues so I want to swap it out. Do I need to spin down the array to do this or can I just hot swap them without that? Quote Link to comment
Bushibot Posted October 2, 2023 Share Posted October 2, 2023 1 hour ago, Bushibot said: I feel like this is dumb question but... my cache drives are setup as ZFS mirrored. I have one drive in the pool that I think is having issues so I want to swap it out. Do I need to spin down the array to do this or can I just hot swap them without that? never mind took it offline to be safe, though adding a new drive and trying to make the old drive a 3rd pool disk did not work, but was having doubt about the old samsung anyway. Quote Link to comment
doogle Posted March 4 Share Posted March 4 Yea, the documentation scattered all about the place is more of a hindrance than a help. That video is older than dirt. I'm gonna create controversy but here goes. This has always been an issue with me and Linux. You have to look in 8 million places to get answers... alot of times the people answering are straight up pricks. And alot of times the info is outdated and won't help. So, you have to take an educated guess as to what you think might work and throw the hail mary. It is one thing that has kept me from embracing linux all along. You either get misleading infomation, or an asshole who wouldn't give you the info if you held a gun to his head. I also don't understand why people keep embracing these technologies that are so out of date it's laughable. Why would I want to use the klunky way to document things on github? Hell, github itself is klunky as hell. All it does it make me see red, wear me out and get like I am now... frustrated. oh well, I'm done. Gonna go figure this out another way.. like usual. Quote Link to comment
itimpi Posted March 4 Share Posted March 4 2 minutes ago, doogle said: Yea, the documentation scattered all about the place is more of a hindrance than a help. The official online documentation is accessible via the ‘Manual’ link at the bottom of the GUI or the DOCS link at the top of each forum page. The Unraid OS->Manual section in particular covers most features of the current Unraid release. Is that how you have been getting to it? Do you have suggestions for improving the layout? Quote Link to comment
jj_uk Posted March 23 Share Posted March 23 What's the process for replacing both cache drives in a btrfs pool? Unplug a drive, plug in the new one, wait for rebuild, then repeat for the other disk? I'm replacing both disks with 1T drives. Quote Link to comment
JorgeB Posted March 23 Share Posted March 23 5 minutes ago, jj_uk said: Unplug a drive, plug in the new one, wait for rebuild, then repeat for the other disk? Basically yes, if the pool is redundant, in doubt post the diags. Quote Link to comment
jj_uk Posted March 23 Share Posted March 23 Thanks for the reply. I found this https://docs.unraid.net/unraid-os/manual/storage-management/#replace-a-disk-in-a-pool. What does "redundant" mean? It's the cache pool, so it's definitely in use! Quote Link to comment
JorgeB Posted March 23 Share Posted March 23 16 minutes ago, jj_uk said: What does "redundant" mean? That the pool can work with a missing device, e.g., a raid1 mirror. Quote Link to comment
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