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dwayneelizondo

Advice on storage/cache for new build

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Hello all, first timer here. 

I wanted to have a single machine where to consolidate all of mine and my gf's media files, instead of having them disseminated on 8+ external hdd as of now - so I downloaded the trial vers of unraid and started messing with it for the past week or so, to get accustomed to it before purchasing anything.

I've been running a simple array with some spare hardware I had around/managed to get for cheap - basically my setup right now is:

 

Z270 Itx motherboard

i5-7400t

4 gb ddr4 ram

Corsair cx450m psu

1x 640gb WD Caviar (from 2008)

 

Right now I only have Plex + deluge set up on the array, and probably won't use anything else - basically I'm trying to make a set-and-forget media server + occasional torrenting.

 

I would like to keep as much of the hardware I already have (except for the hdd, which is basically more than ancient), so I was thinking of going with 1x 4TB WD Red for parity and 2x 4TB WD Red for data.

 

Question is, do you really think that for this kind of use I would need a cache drive? Or I can just go ahead with my purchase, and have deluge work directly on the array (I don't expect to do heavy torrenting, just around a dozen gigs of downloads a week). I've seen also topics about having a drive outside the array with unassigned devs. to be used as storage for torrents, but I don't want to overcomplicate things too much.

Thanks

 

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I recommend a cache SSD for your applications. Having the applications working storage on cache SSD gives better performance and will allow the HDDs in the array to spin down. If you use the array for the applications they may keep the array disks spun up and parity updating.

 

You can still configure your downloads to go straight to the array, and of course your media would be stored on the array. If you don't cache any user share writes and only use it for applications working storage you don't need a very large SSD.

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I would also recommend a cache drive, it is the defacto application drive for unRAID.  And trurl's recommendation to use an SSD is excellent.  That said, you can use one of your HDs for the cache drive if you're not ready to make the jump to an SSD.

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15 hours ago, tdallen said:

I would also recommend a cache drive, it is the defacto application drive for unRAID.  And trurl's recommendation to use an SSD is excellent.  That said, you can use one of your HDs for the cache drive if you're not ready to make the jump to an SSD.

 

Thanks for the reply -  I'll probaly use the old hdd as cache for the first weeks till I can upgrade to an ssd. btw do you think that 120gb could be enough, or should I get something bigger? Also, I was thinking about buying an m.2 sata, so not to clog up all my sata ports (I should be ok with 8tb of data disks for the foreseeable future, but with a free sata port I could upgrade easily with another 4tb wd red).

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8 minutes ago, dwayneelizondo said:

Also, I was thinking about buying an m.2 sata, so not to clog up all my sata ports

Make sure you are actually able to use all your ports at once. Some boards steal a sata port if you use a M.2 Sata card.

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10 hours ago, dwayneelizondo said:

btw do you think that 120gb could be enough

My cache drive is about 70GB used right now.  It's got a 20GB docker image file, and ~50GB of random stuff - files to be uploaded, recently downloaded, the data files for various Dockers including Plex and several others, etc.  So 120GB would be fine as a starting point since you have the drive already but I'd advise anyone buying a drive to start at 250GB.

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Posted (edited)
On 4/16/2018 at 5:30 PM, trurl said:

I recommend a cache SSD for your applications. Having the applications working storage on cache SSD gives better performance and will allow the HDDs in the array to spin down. If you use the array for the applications they may keep the array disks spun up and parity updating.

 

You can still configure your downloads to go straight to the array, and of course your media would be stored on the array. If you don't cache any user share writes and only use it for applications working storage you don't need a very large SSD.

I've upgraded from V5 to V6 yesterday, under V5 i used my ssd (mounted as 'cache') as the one drive on which all my apps where running, indeed to prevent unneccesary spinup of physical disks, e.g. when downloading. So i've setup V6 the same way, i disabled the cache drive under 'global share settings'. So far so good.

 

The problem is, when unraid started for the first time, it put 4 folders (system, appdata, isos and domains) on the last physical disk in my array (disk9) so they became user shares. But... i want those folders to be exclusively on the ssd (cache) drive. In the settings for the share, you can include or exclude drives, but the ssd (cache) can not be selected there. I did set 'use cache disk only' on the share settings.

 

So i copied these 4 folders to my ssd (cache) and removed them from disk9... but now unraid does not show them as user shares anymore? Is that a problem?

So, the question is, how can i place these shares exclusively on my ssd while maintaining them as user shares on the system?

Edited by jowi

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You shouldn't disable cache drive in Global Share Settings. Instead you should just set each of your user shares to Use cache: No. That is the default for a user share so if you haven't been caching them you should be OK. Those 4 "system" folders are supposed to be cache-prefer user shares. Probably if you just change the Global Share setting and restart the array it will be all square.

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If i enable the cache drive, i get both a 'user' folder and a 'user0' folder... that is also not what i want.

i do NOT want to use the ssd as a cache drive, i don't want the mover active, just as a fast, unprotected non-array drive for apps, like i did with v5.

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Using it as a cache drive is the simplest way. If you don't have any user shares set to cache-yes then no user share will use it except for those "system" folders. And unless you actually take the trouble to set a user share to cache-yes, it defaults to cache-no. It is called a cache drive and unRAID manages it as a cache drive, but if there are no cache-yes user shares, then no user shares will be cached or moved.

 

Another approach is to use Unassigned Devices to mount it outside the array, but really just assigning it as cache is easier and will do everything you want it to do and will also do nothing you don't want it to do.

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Like i said, if i enable it as a 'real' cache drive, unraid adds a 'user0'  folder next to the user folder, and it also has all the inner folders... something tells me that is not good.

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1 hour ago, jowi said:

Like i said, if i enable it as a 'real' cache drive, unraid adds a 'user0'  folder next to the user folder, and it also has all the inner folders... something tells me that is not good.

 

It is completely normal. user0 is just the user shares excluding cache. user is the user shares including cache. Mover works by moving from cache to user0 for cache-yes shares, and moving from user0 to cache for cache-prefer shares.

 

In your case, since you aren't going to have cache-yes shares, and everything in the "system" folders will already be on cache, mover won't have anything to move.

 

There is typically no reason for anyone to even think about user0 (or even know it exists), it is just there for mover to work with.

 

I use my server in a very similar way as you are wanting to. I have no user shares that are ever moved, but I do have some user shares on cache, including those "system" folders.

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Is it neccesary to have these 4 folders as user shares defined anyway? (system/isos/domain/appdata)?

I've put them all on /mnt/cache/... now, made sure docker and vm etc are also pointing there, everything is working fine.

 

Since they are defined as user shares, unraid created them on my disk9 drive. If i just delete them from disk9, they are no longer user shares, and everything should work fine, is it not?

Or are there some secret processes etc that need these 4 folders to be defined as shares?

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2 hours ago, jowi said:

Is it neccesary to have these 4 folders as user shares defined anyway? (system/isos/domain/appdata)?

 

They are the default locations used when setting up VMs and dockers. I only have appdata since I set mine up long ago before these defaults were made. As long as you take care to make sure everything relating to dockers and VMs are using a valid path you don't really have to have them.

 

2 hours ago, jowi said:

Since they are defined as user shares, unraid created them on my disk9 drive. If i just delete them from disk9, they are no longer user shares, and everything should work fine, is it not?

 

If your dockers and VMs are working and not using those shares then you don't need them. The only reason unRAID created them on an array disk is because you told it to not use cache. Normally it would have created them on cache.

 

It sounds like you have things worked out, just a little differently than usual. There is no requirement to allow user shares to include the cache disk but that is the usual and default configuration. And that default configuration would have worked in the way you wanted to use your cache disk. That is the way I am using cache and I have it included in user shares.

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