14 days in, Feedback, Cache Issues, asking for Support


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hi! i'm a new unraid user and liking the system very much so far. i'm moving from a synology ds, built a cheapish 40tb desktop nas and am in the process of moving all applications and data to my new unraid system. in the past 2 weeks i've researched everything that was needed for the initial setup, tried and configured different dockers and became familiar with most of its options. i've followed besst practices where i could.

 

now, after 14 days i'm stuck with issues i ran into and am asking for support/feedback. it is moving data, using cache, using dockers that give me quite the headache because the system becomes unusuable when those issues appear.

 

-the system becomes unusable slow when running the mover. webui is not reacting, dockers not reacting, sometimes crashing. i am now running the mover at night. it's not a super big issue but it leaves a sour aftertaste.

 

-moving data manually peaks the cpu with 100% on single cores, sometimes many cores. moving data generally is a pain, it appears it's cpu or IO issues.

 

-this also happens while normal operation. sometimes rutorrent bugs out although it is barely doing anything. also using 100% cpu, i kinda suspect this happens also when it moves data (fo the finished folder).

 

-when these issues appear other applications are affected, namely when rutorrent bugs out or the mover is running, plex dies on me, which is quite frustrating to say the least.

 

- 4 out of my 10 drives are spinning all the time. my understanding is that using the cache drive the array disks would only need to spin up at night when the mover is running. in the past 2 weeks the 2 parity drives and the first two data drives (where all my data is) never spun down.

 

with all this happening i thought i split the mdeia folder in two, to circumvent all those ssd cache problems, leaving only appdata and downloads cached, creating a new library share that holds all media on the array without any caching at all.

 

while this is doable i guess, it would also kinda leave a sour aftertaste because i'd have it stuck in the back of my head that there is a cache ssd issue and i can't fully use the cache feature. also it would mean that my array disks would be spun up most of the time which would mean a couple of additional drawbacks (energy, noise, lifetime).

 

my question with those issues now are:

 

-is there a general ssd cache writing data bug that i'm running into? can i somehow resolve this? what can i do to figure it out?

-is my setup correct or did i maybe make something wrong causing those issues i described? did i miss any best practices?

 

 

thank you very much for any feedback and support, looking forward on becoming a happy unraid user :)

 

unraid-diagnostics-20210221-1325.zip

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i unfortunately cannot give 100% answers. I do know i had similar issues (to a lesser degree, but still) with a bad quality SSD (was the cheapest drive i could afford , but i brought the system to a halt everytime large write/read actions was running on it. Dockers didnt crash, but a plex database query for example timed out in many cases.

 

Maybe see if system stability increases when bypassing the cache( guess it is a given that it will), and test from there onwards.

maybe check if your PCIE bus is not being stressed?  (eg all the drives pushing through one x16 slot?) -> low chance, but it happened with my 24-drive system. (see the diskspeed docker)

 

my ideas so far. would love to know what the cause ise

 

 

 

 

 

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Recommended setup was use UD plugin to mount a SSD which host VM / Docker ( avoid use array or share-cache ) this should solve most problem.

 

Array not suitable for heay multiple read and write application.

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On 2/21/2021 at 2:33 PM, Neo_x said:

 a bad quality SSD

 

hi, thanks for the tip. turns out the ssd i got was indeed faulty. i noticed that it was running hot, but didn't think any more of it. i changed the ssd for the cache and now the system performs much better. using the mover is still slowish, but it's not killing the whole OS. thanks again! cheers

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