Near constant Disk churning with Plex
Posted: Thu Dec 06, 2018 5:46 pm
I've installed Plex on my TS-251Plus and loaded about 200 movies. This is the only current purpose of the NAS; I bought it for another purpose but have yet to put it into service. I finished loading the last movie around June; it is now December so I would hope any background processing of thumbnails, etc is complete . I also haven't watched a single movie in at least 2 months, and only watched maybe 10-20 in total since loading ... so it is very lightly used to say the least. There are two drives (4 TB each) in standard raid 1 config (1 group), 1 storage pool, configured as 3 volumes, none more than 50% full. Model - Seagate ST4000VN008. I do have 'reclaim' set on, but it's supposed to run daily at 2am and I'm observing the noise all day (currently it's midnight, so 22 hrs since last reclaim should have run). And since I don't use the box, there should be no changes of any sort that would trigger any kind of reclaim. I've updated firmware regularly to see if it addresses this issue (does not). Currently at 4.3.5, updated as of today).
I sit next to the NAS box. the drives are being heavily accessed almost constantly. They go idle for maybe 60 seconds, and then they start again, and the noise goes on for several minutes, then there's the brief respite before starting again. I've 'disabled' the Plex service on the NAS and the noise significantly reduces with that action, so I'm pretty sure it's Plex that is doing it. Also, of some interest maybe this. There are two types of noise. There is a rather continuous 'rumble' that I'm quite familiar with as that is general disk access sound, and then every 5 seconds, the two drive lights 'blink' and that is associated with a much higher pitch sound that is also familiar to me as disk access, but of a different sort (possibly the heads are being parked? really not sure). But the second, brief, sound is the only one that correlates with the two green lights blinking; otherwise, the green lights are solid on.
CPU usage is constantly fluctuating around 2-40% with nothing (externally) going on. It will show 2, then 12, then 2, then 12, then 36, then 60, 29, 2, etc. None of the spikes in activity correlate to the disk access noise. Summary at the top of the resource monitor shows Processes - Total 152; running 2; sleeping 148; uninterruptible 0; stopped 0; zombies 2 (Zombies fluctuates). Resource monitor shows Plex group of processes (4) as never using more than 1% CPU; all 4 plex services are 'sleeping' but do show 0.2, 0.4% activity on and off. Within the Plex group, DLNA service is the 'most' active (though sleeping) with fluctuations from 0 to 0.7%. But the most active group by far is 'system processes' (81 in all) and of them, 'Kernel_processes' is by far the biggest user and seems to account for almost all CPU utilization (no other 'system processes' members go over 1%).
Memory is 87% available / 12% used. (I have 8 GB)
Network utilization is negligible - maybe 1% and probably correlates to me viewing usage charts on the NAS.
Disk activity (according to resource monitor) is showing negligible r/w access - I sit here listing to the disks churn away constantly and the reads / writes show a constant 0/sec, 0/sec with a few blips to 1, 2/sec. This is one of the frustrating elements ... it's not reflecting in disk activity at all!
When I launch 'App Center', the green access lights blink like crazy for several minutes and I hear the more obvious disk access noise. This reinforces the above observation; there are two types of noise from the box, and only one of the noises correlates to lights blinking.
When I stop the Plex service, the disk noise doesn't entirely go away (at least not immediately), but there are now longer periods of inactivity. CPU utilization on the NAS still fluctuates heavily and kernel_processes is still the main culprit. In fact, I see no drop in CPU utilization with Plex off.
I'm truly puzzled by this and wonder if anyone has any idea what might be going on!
Thanks
I sit next to the NAS box. the drives are being heavily accessed almost constantly. They go idle for maybe 60 seconds, and then they start again, and the noise goes on for several minutes, then there's the brief respite before starting again. I've 'disabled' the Plex service on the NAS and the noise significantly reduces with that action, so I'm pretty sure it's Plex that is doing it. Also, of some interest maybe this. There are two types of noise. There is a rather continuous 'rumble' that I'm quite familiar with as that is general disk access sound, and then every 5 seconds, the two drive lights 'blink' and that is associated with a much higher pitch sound that is also familiar to me as disk access, but of a different sort (possibly the heads are being parked? really not sure). But the second, brief, sound is the only one that correlates with the two green lights blinking; otherwise, the green lights are solid on.
CPU usage is constantly fluctuating around 2-40% with nothing (externally) going on. It will show 2, then 12, then 2, then 12, then 36, then 60, 29, 2, etc. None of the spikes in activity correlate to the disk access noise. Summary at the top of the resource monitor shows Processes - Total 152; running 2; sleeping 148; uninterruptible 0; stopped 0; zombies 2 (Zombies fluctuates). Resource monitor shows Plex group of processes (4) as never using more than 1% CPU; all 4 plex services are 'sleeping' but do show 0.2, 0.4% activity on and off. Within the Plex group, DLNA service is the 'most' active (though sleeping) with fluctuations from 0 to 0.7%. But the most active group by far is 'system processes' (81 in all) and of them, 'Kernel_processes' is by far the biggest user and seems to account for almost all CPU utilization (no other 'system processes' members go over 1%).
Memory is 87% available / 12% used. (I have 8 GB)
Network utilization is negligible - maybe 1% and probably correlates to me viewing usage charts on the NAS.
Disk activity (according to resource monitor) is showing negligible r/w access - I sit here listing to the disks churn away constantly and the reads / writes show a constant 0/sec, 0/sec with a few blips to 1, 2/sec. This is one of the frustrating elements ... it's not reflecting in disk activity at all!
When I launch 'App Center', the green access lights blink like crazy for several minutes and I hear the more obvious disk access noise. This reinforces the above observation; there are two types of noise from the box, and only one of the noises correlates to lights blinking.
When I stop the Plex service, the disk noise doesn't entirely go away (at least not immediately), but there are now longer periods of inactivity. CPU utilization on the NAS still fluctuates heavily and kernel_processes is still the main culprit. In fact, I see no drop in CPU utilization with Plex off.
I'm truly puzzled by this and wonder if anyone has any idea what might be going on!
Thanks