Why Does Plex Get Slower With Extra Resources
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So I did post a question about this on the Plex forums, but I figured I'd ask this here as well. I have a high amount of resources for a home lab (Dell PowerEdge R510, Intel Xeon X5660 2.8/12M/1333 (x2), 4 TB SAS Dell Enterprise HD's (x4) in a Raid 10, 64 GB Dell DDR3, etc). I noticed that when I allocate a lot of resources to it, it loads content more slowly and generally runs worse, but if I reduce the resources to 8 GB of memory and 2 vCPU's it runs very well. My question is why?
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Could be any number of things without digging into Plex specifically. In all cases, excess of resources causes systems to slow, that's to be expected. But under normal conditions it is unnoticeable. But it could be as simple as it loading too many resources into memory or a bad caching system.
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What constitutes too many resources though? I am definitely far below what my server hardware could handle. A media server is the type of server that can go from sub 1% utilization to 100% at the drop of a hat. The unused resources increase exponentially if I have multiple users transcoding (as an example), yet when it's unused it would drop to sub 1% again.
How is this resolved?
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I have 24 threads available. I allocated 4 of them to this task and 32 GB of memory, which is exactly 50% of the memory. There are no other VM's running in the hypervisor currently (online or offline).
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@wirestyle22 said in Why Does Plex Get Slower With Extra Resources:
What constitutes too many resources though?
More than the system has a use for.
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@wirestyle22 said in Why Does Plex Get Slower With Extra Resources:
I have 24 threads available. I allocated 4 of them to this task and 32 GB of memory, which is exactly 50% of the memory. There are no other VM's running in the hypervisor currently (online or offline).
Does the system ever use all of those resources?
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@scottalanmiller said in Why Does Plex Get Slower With Extra Resources:
@wirestyle22 said in Why Does Plex Get Slower With Extra Resources:
I have 24 threads available. I allocated 4 of them to this task and 32 GB of memory, which is exactly 50% of the memory. There are no other VM's running in the hypervisor currently (online or offline).
Does the system ever use all of those resources?
Rarely, but it does. I've shared my media server with a lot of family etc, so it CAN hit that ceiling but everyone has to be using it at the same time and we're all different time zones.
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@wirestyle22 said in Why Does Plex Get Slower With Extra Resources:
@scottalanmiller said in Why Does Plex Get Slower With Extra Resources:
@wirestyle22 said in Why Does Plex Get Slower With Extra Resources:
I have 24 threads available. I allocated 4 of them to this task and 32 GB of memory, which is exactly 50% of the memory. There are no other VM's running in the hypervisor currently (online or offline).
Does the system ever use all of those resources?
Rarely, but it does. I've shared my media server with a lot of family etc, so it CAN hit that ceiling but everyone has to be using it at the same time and we're all different time zones.
So you have to decide between tuning for slow times or peak ones
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@scottalanmiller said in Why Does Plex Get Slower With Extra Resources:
@wirestyle22 said in Why Does Plex Get Slower With Extra Resources:
@scottalanmiller said in Why Does Plex Get Slower With Extra Resources:
@wirestyle22 said in Why Does Plex Get Slower With Extra Resources:
I have 24 threads available. I allocated 4 of them to this task and 32 GB of memory, which is exactly 50% of the memory. There are no other VM's running in the hypervisor currently (online or offline).
Does the system ever use all of those resources?
Rarely, but it does. I've shared my media server with a lot of family etc, so it CAN hit that ceiling but everyone has to be using it at the same time and we're all different time zones.
So you have to decide between tuning for slow times or peak ones
So, if these resources were in use constantly I would not slow down but because they aren't it becomes a resource management problem? What is the difference between in use resources vs. our of use resources to the kernal?
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@wirestyle22 said in Why Does Plex Get Slower With Extra Resources:
@scottalanmiller said in Why Does Plex Get Slower With Extra Resources:
@wirestyle22 said in Why Does Plex Get Slower With Extra Resources:
@scottalanmiller said in Why Does Plex Get Slower With Extra Resources:
@wirestyle22 said in Why Does Plex Get Slower With Extra Resources:
I have 24 threads available. I allocated 4 of them to this task and 32 GB of memory, which is exactly 50% of the memory. There are no other VM's running in the hypervisor currently (online or offline).
Does the system ever use all of those resources?
Rarely, but it does. I've shared my media server with a lot of family etc, so it CAN hit that ceiling but everyone has to be using it at the same time and we're all different time zones.
So you have to decide between tuning for slow times or peak ones
So, if these resources were in use constantly I would not slow down but because they aren't it becomes a resource management problem?
Depends on what you consider slowing down. Having an engine too big for normal driving takes a toll on highway efficiency. But if you NEED it from time to time, then you'd have less power than necessary when you need it. If you were using all your resources all the time, there is nothing to slow down from, it's just at capacity.
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@wirestyle22 said in Why Does Plex Get Slower With Extra Resources:
What is the difference between in use resources vs. our of use resources to the kernal?
One is being used to service a need, the other is just in the way and has to be managed without adding any value.
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@scottalanmiller said in Why Does Plex Get Slower With Extra Resources:
@wirestyle22 said in Why Does Plex Get Slower With Extra Resources:
What is the difference between in use resources vs. our of use resources to the kernal?
One is being used to service a need, the other is just in the way and has to be managed without adding any value.
So if I had a need to use these resources Plex would still be slow but there would be a good reason whereas now it would be slow for no reason. That's what you're saying?
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@wirestyle22 said in Why Does Plex Get Slower With Extra Resources:
@scottalanmiller said in Why Does Plex Get Slower With Extra Resources:
@wirestyle22 said in Why Does Plex Get Slower With Extra Resources:
What is the difference between in use resources vs. our of use resources to the kernal?
One is being used to service a need, the other is just in the way and has to be managed without adding any value.
So if I? had a need to use these resources plex would still be slow but there would be a good reason whereas now it would be slow for no reason. That's what you're saying?
Right. You must decide what you are going to tune for. Throwing resources at a computer doesn't just make it faster, it only makes it faster if there is a way to utilize those resources. When a workload runs at different rates, you have to decide what you are tuning for... max, average, 95th percentile, etc.
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Think about a closet. If you have five shirts, you need a closet to put them in. But not a big closet. Making the closet bigger will not speed up finding your shirt in the morning. And if you then have to clean the closest and sometimes you lose your shirt in it because it is so big, it actually slows you down. An unnecessarily large closet actually hurts you instead of helps you. But if you sometimes need a thousand shirts stored in there, you might determine that having a big closet is worth the wasted space and energy to handle the occasions when loads of shirts arrive and need to be stored.
