SSD Cache and SSD Appdata

[statecowboy]

Hi guys, would appreciate some feedback on something I'm considering.  I currently have 2 SSDs in my setup.  Both are mirrored by default and serve appdata and cache needs.  I've noticed when my downloading program is running/processing, my webserver (organizr) and other apps suffer.  Obviously this is due to the work being done on he SSD for cache needs.  I was considering putting a third SSD in my machine to just serve cache needs.  So, appdata would be left alone to function only as needed.  Would you think this would help speed things up?  Any potential pitfalls with this approach?

 

EDIT - Or, would it be preferred to just turn off cache for writes?  Is there a significant speed difference in writing directly to the array rather than to cache first?  I generally average around 90 MB/sec downloads when using SSD cache.

Edited February 2, 2018 by statecowboy

[statecowboy]

Any ideas?  I've been doing a lot of reading and I'm not sure if this would work or not.  I saw some people have issues running dockers from a UD.  That said, it would greatly improve performance in my situation as I need the cache drive SSDs to be available for what they do (namely speeding up downloads and processing) without dockers suffering in performance while this occurs.

[Squid]

Just now, statecowboy said:

I saw some people have issues running dockers from a UD

Should be zero problems.  The only issue per se is to set any reference in a host mapping on the container when using a UD mount to RW:Slave  Even without that change, the system will work properly 99% of the time.

[CHBMB]

I run all my containers from a SSD mounted via UD as RW:Slave.  Zero issues.

[statecowboy]

Thank you both for your replies.  Just wanted to be extra cautious.  

 

Edit - I have the drive formatted as xfs, for what it's worth.  I don't suspect that will cause any issues.

 

One more question - should I just move my appdata folder over to the new drive (as well as update containers to point to that location), and UNRAID will rebuild my docker.img?  Or, should I move docker.img as well?

Edited February 3, 2018 by statecowboy

[CHBMB]

Thank you both for your replies.  Just wanted to be extra cautious.  
 
Edit - I have the drive formatted as xfs, for what it's worth.  I don't suspect that will cause any issues.
 
One more question - should I just move my appdata folder over to the new drive (as well as update containers to point to that location), and UNRAID will rebuild my docker.img?  Or, should I move docker.img as well?

You can move the lot, just make sure the docker service is stopped and you update the location of docker.img in the settings before restarting it. You'll also need to update the location of appdata in each container template too and ensure that it's mounted as RW:slave. My drive is also formatted as XFS.

Sent from my LG-H815 using Tapatalk

[statecowboy]

To be extra cautious....would this work?  Backup appdata using appdata backup/restore.  Create folder in unassigned drive called "Apps".  Extract contents of backed up apps to this new "Apps" folder.  Update docker containers with path moved from old "/mnt/user/appdata/appnamehere" to "/mnt/disks/Samsung_SSD_850_EVO_500GB_S3PTNF0JB57874H/Apps"?

 

Anything in particular I need to do about "/mnt/user/system/docker/docker.img"?

 

UPDATE - sorry CHBMB, looks like you beat me to the punch.

 

Edited February 3, 2018 by statecowboy

[statecowboy]

31 minutes ago, CHBMB said:

You can move the lot, just make sure the docker service is stopped and you update the location of docker.img in the settings before restarting it. 

Sent from my LG-H815 using Tapatalk
 

At the risk of sounding extra dense.  To clarify what you mean.  Are you saying I need to create a system/docker folder in the UD?  Or just some location (I can choose to call it whatever I want) that docker points to?  I assume docker will automatically generate the docker.img, right?  Also, can I delete the old docker.img from /mnt/user/system/docker/docker.img afterwards?

[CHBMB]

No need to create anything just stop the docker service and move your appdata and docker.img to the new location, specify where that is in the docker settings page, restart the docker service and edit each template to reflect the new location of the appdata.

[statecowboy]

Thank you - worked flawlessly.  Used krusader to copy over all the files and shaved off a few hours versus using smb.

 

[IamSpartacus]

On 2/3/2018 at 12:14 PM, CHBMB said:

I run all my containers from a SSD mounted via UD as RW:Slave.  Zero issues.

 

How do you handle backups of your appdata since it's on an unprotected disk?  I'd like to do something similar but I'll need some kind of backup/redundancy for my appdata.

[statecowboy]

1 hour ago, IamSpartacus said:

 

How do you handle backups of your appdata since it's on an unprotected disk?  I'd like to do something similar but I'll need some kind of backup/redundancy for my appdata.

I use this:

And just have the settings configured to point to where my apps/dockers are and they get backed up to the array.  I also use the duplicati plugin and have it set to back up my apps folder once a week to google drive.

[CHBMB]

I do the same.....

 

@IamSpartacus Where you running your appdata at the moment?  On the protected array?

[IamSpartacus]

36 minutes ago, CHBMB said:

I do the same.....

 

@IamSpartacus Where you running your appdata at the moment?  On the protected array?

 

Currently I'm not running any of my docker apps in UnRAID.  I use UnRAID for mass storage and run my docker apps in Linux VMs on a two node VMware cluster for redundancy.  However I'm looking to consolidate all my hardware into an All-in-one server and thus run my apps from UnRAID.  But I need a good way to backup and replicate my appdata both locally to the protected array and to an off-site UnRAID server that I have.

[CHBMB]

CA Appdata Backup Restore will do that, makes a tar file of you appdata set to a schedule.  Guess you could rsync that over ssh to an offsite backup or just rsync the raw files.

[IamSpartacus]

On 2/6/2018 at 6:36 PM, CHBMB said:

CA Appdata Backup Restore will do that, makes a tar file of you appdata set to a schedule.  Guess you could rsync that over ssh to an offsite backup or just rsync the raw files.

 

Rsyncing the raw files would take FOREVER the way Plex's folder/file structure is setup.  A tar file might work though.

 

I'm trying to brainstorm how I want my flash media configured.  I basically have room in my server for 4 flash devices (2 x M.2. SSD's, 2 x 2.5" SSDs).  I definitely want my appdata off of my cache pool but maybe even want to separate my VMs and Downloads.  When my downloads are extracting it really kills the performance of the cache pool.  So much so that my 1Gbps downlods will get cut down from say 80MB/s all the way down to 20MB/s during the extraction process.

 

EDIT:  Sorry to hijack this thread @statecowboy.  I can start a new one if you'd like.

Edited February 8, 2018 by IamSpartacus

[statecowboy]

No worries on hijacking the thread.  I ended up stopping all dockers except krusader and transferring all dockers and my dockers.img that way.