Mover Schedule

[Lo Key]

Just curious on what most people have their mover schedule set to.  I'm still pretty new to Unraid so I'm still checking out all of the settings.  Right now I have all of my shares set to Yes for "Use cache drive".  I set it to this originally because I was moving so much data over at first from my old storage I thought it might speed things up.  Now that I'm fully migrated, I still haven't changed this.   The only thing that is writing somewhat regularly to Unraid is downloads in nzbget.

 

I guess, to sum up, here are my questions:

 

1. Should I set any shares that aren't written to often to No for "Use cache drive" so they are protected immediately?

2. Are there any disadvantages to running Mover hourly instead of once per day?  I understand there will be more disk usage but I'm not really moving 10's of GB at a time onto the array anymore so I would think running more often shouldn't impact performance too much, would it?

 

Thanks.

 

Edited October 18, 2017 by Lo Key

[tdallen]

Hello and welcome.

 

Using the cache drive to cache writes to the array isn't inherently better than writing directly to the array.  It's an option, you should just use it if it makes sense.  I think you have a good grasp of the issues - writes to the cache drive somewhat faster than to the array, but they aren't protected by parity until mover runs.  I'm not a fan of running mover more frequently, but again it's an option.

 

Personally I don't cache writes to the array at all.  If I were sitting in front of my PC constantly waiting for writes to my server, I might use the cache drive for write-caching.  But most of my writes are unattended or I start up a copy and walk away.  Further, when I want to copy a large amount of data I turn on Turbo Write (in my sig), which is almost as a fast as write-caching in many situations - but you're writing directly to the array.

 

If you decide to turn off use of the cache drive for certain shares, make sure to run mover first so you don't have any data get stuck on the cache drive.  I'd suggest giving it a try.  Having your data immediately protected by parity is a good thing, and writes to the array using large, modern hard drives are pretty fast.  Give it a try and if your reaction is "OMG this is too slow" then you can either turn it back on, or look at Turbo Write.

[DZMM]

6 hours ago, tdallen said:

 

 

Personally I don't cache writes to the array at all.  If I were sitting in front of my PC constantly waiting for writes to my server, I might use the cache drive for write-caching.  But most of my writes are unattended or I start up a copy and walk away.  Further, when I want to copy a large amount of data I turn on Turbo Write (in my sig), which is almost as a fast as write-caching in many situations - but you're writing directly to the array.

 

 

I totally agree with this sentiment.  I use my SSD cache mainly to reduce disk spin-ups and noise as my machine is about 1m away from where I work, rather than to get faster write speeds which don't really matter as they tend to be background activity. 

 

To avoid the issue of what frequency to use mover,  I use this script to only run mover when my cache gets to 85% capacity i.e. for my 500GB cache mover doesn't run until it hits 425GB.  The 85% limit has worked perfectly for me as the cache empties fast enough if its filling up with new files and files just stay on the cache otherwise.

 

 

I tend to set my smaller shares like 'books' and personal shares on the cache as 'only' or 'prefer' and my larger shares like 'downloads' 'import' and 'media' as 'yes' as there isn't enough room on the cache to hold these for long.

 

I'd recommend getting a cache pool if you haven't got one yet though if you go down this road or aren't flushing your cache regularly.

 

[Pixeldieb]

Mind if i chime in on this question?
So i have MASSIVE media files needing to get offloaded quickly, but then there is time to securely back them up in the array.

Working on film sets to manage data safety and the media cards are often 400 - 800 GB of Data that has to be backed up fast (to make room for the next card) and stored redundant (background process) to ensure integrity.

I was thinking of using 2 m.2 NCME cards (RAID 1) to offload / as cache drives and using the script to dump everything at half capacity of the Offload drives.

 

MEDIA ---via USB 3---> NVME (Cache) ---reaching 50% Capacity---> backing up to the Array

 

Since this is my first Unraid build (havent finished the details yet) i might be wrong on this idea of using superfast cache drives. Does the frequent backup hurt the system?