High CPU usage

[TravisT]

I have a Freenas box that has been chugging along for some time now. I began to notice some problems with samba over the past months, and noticed there was a bug reported in one of the older builds (that I had been running). I upgraded to the latest version, but I'm still seeing the user cpu usage basically pegged 97-99% avg.

Another anomoly I've noticed are repeats of this error (not sure if it's related):

Freed frame ../source3/smbd/open.c:3510, expected ../source3/modules/nfs4_acls.c:936.

 

[cyberjock]

Define the "latest version". 9.2.1.x has some nasty CPU hogging bugs. So if you upgraded to any of those you didn't do yourself any favors. You also didn't mention your hardware at all...

 

[TravisT]

9.2.1.3-Release-x64.

I saw in 9.2.1.2 I believe that there were some samba issues that were said to be fixed in 9.2.1.3 IIRC. Apparently, they aren't.

Like I said, this box has been running for several years now with very few problems so the hardware is a bit dated. I'm running a AMD Sempron 140 and 16G RAM. 3 disk raid-z using 2TB disks for general file/media storage and four 1TB drives in a striped/mirrored volume for iSCSI targets for VMs. This is all for a home network with just a couple users/VMs.

 

[cyberjock]

Yeah, the CPU hogging problems were allegedly fixed in 9.2.1.1, then 9.2.1.2, and then 9.2.1.3. I can vouch that many users are on 9.2.1.3 are still having problems. :(

I know the new Samba in 9.2.1+ is much more CPU intensive than the old Samba, so your problem may be that your poor Sempron 140 can't keep up with the workload. That CPU is 4x slower than the CPU we typically recommend on the lowest end, the Pentium G2020. Nowadays we've been recommending the Pentium G3220 since it's the current generation technology and a few dollars more than the G2020. But even it is like 20% faster than the G2020.

 

[TravisT]

Yeah, the CPU hogging problems were allegedly fixed in 9.2.1.1, then 9.2.1.2, and then 9.2.1.3. I can vouch that many users are on 9.2.1.3 are still having problems. :(

That explains it...

So until I can upgrade the hardware, what's the recommended course of action to get thing working smoothly again? Downgrade?

I also recently noticed that my poor little Sempron 140 (that was unlocked to an athalon II x2) is not showing that way anymore. That may offer a bit more performance, but I'll have to look into what changed and caused it to revert back to a single core.

 

[cyberjock]

Not sure. I'm a little in shock right now that you'd want to build a server for reliability, then take the risk of unlocking a CPU that may have manufacturer's defects. That's just scary to me with regards to your data. Many people have had CPUs that they unlocked and claimed it was fine for a long time, but there really were manufacturer's defects that weren't obvious just by a cursory test and it bit them much later. It's literally impossible for you, as the end user, to test all of the paths for data inside a CPU just by booting up and using an OS. Assuming a given CPU has a fault, it's something you might never encounter or something you might encounter before you even POST the box.

As for your core disappearing it could be that FreeBSD has dismissed the unlocked core because of excessive processing faults. I know it has some weird stuff it does when it finds faulted hardware. It does something to no longer use what it deems as "faulted" hardware without requiring the system to go down.

Overall, i'm not really sure. I run the other direction as fast as I freakin' can the second someone talks about unlocking cores or overclocking with FreeNAS. It's quite silly to want a reliable system, then to do something as risky as overclocking and unlocking cores.

/starts running the other direction as fast as he can

 

[TravisT]

Good point, didn't think of it from that perspective. With that said, is it possible to downgrade an installation without jacking up everything, or should I start spec'ing a new system?

BTW... you can stop running, I'm over the core unlocking!

 

[cyberjock]

/starts running back as fast as he can

/catches his breath

If you backed up your config file before the upgrade, then you can just upgrade to whatever version you want and import the old config file. If you don't have a backup you have to stick with the version you have.

Of course, if you chose to upgrade your zpool to the latest version since upgrading(you must do this from the CLI so you'll know if you did it) you cannot ever go back to any version that doesn't support your zfs version and feature flags.

Assuming you can go back, I'd recommend 9.2.0. That's what I consider the latest stable version from my perspective.