Identifying bottleneck - Mover action cripples machine

[morgish]

Hi Everyone,

This is my array: 

 

Tonight I was watching a movie which is currently on Disk 1. 

The mover job started to move a 60GB file from the Cache to Disk 2 and throughput to the media box came almost to a complete hault. 

I tested pulling the same file to my desktop computer while mover was still running and could only manage 1MB/s. 

So when the mover job is running, IO on unused (during mover) disks is impacted. 

 

Can someone help me identify what I can do to reduce the impact on the machine when mover is running? 

Also the Cache is 2x 128 SSD's in Raid 0 (BTRFS) to make 256GB. 

Appreciate any help.

Cheers,

Kris

[itimpi]

You need to provide more information!   Details of your hardware configuration would be useful so we can get a view of whether you are likely to have I/O bottlenecks.    Also the system diagnostics  (Tools->Diagnostics) covering a period where you experience this issue might be a good idea.

[trurl]

As itimpi said above.

 

You might also want to reevaluate how you are using cache. Many of us don't even cache user share writes. Mostly I just use cache for cache-only shares; for apps, temporary files such as recording, and copies of files I want frequent, fast, read access to. Most writes to my server are unattended downloads and backups. Since I am not usually waiting for the writes to complete anyway, they go directly to the protected array.

 

Also, mover is typically scheduled to run when you won't be using the server.

 

[tdallen]

11 minutes ago, trurl said:

Many of us don't even cache user share writes.

+1

[Perforator]

And many of us do.

[kizer]

I personally have my Mover set to 7AM and my Plex Server set to update its Libraries at 8AM. 

That way I'm not even using it when everything hits. Also if I do happen to watch something on Plex in the previous evening my Libraries are typically up to date with the new content, but I have it set so I can avoid any bottlenecks. 

 

Just like my HandBrake Encodes and whatever else. I schedule everything around when I'm not using my machine not to Make it easier on my Machine, but to keep myself out of Hot Water with the misses and my two boys.