Unix and Linux Stack Exchange
Unix and Linux Stack Exchange

Questions tagged [tuning]

20 questions
13
votes
3 answers

How to change the length of time-slices used by the Linux CPU scheduler?

Is it possible to increase the length of time-slices, which the Linux CPU scheduler allows a process to run for? How could I do this? Background knowledge This question asks how to reduce how frequently the kernel will force a switch between…
sourcejedi
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systemd slices even with low CPUShare heavily affect system responsiveness

I've created custom slice (so now I have 4 slices user, system, machine, important) and assigned huge number to CPUShares. System felt really unresponsive under high load in this slice, what seems to be logical considering enormous CPUShares value.…
Lapsio
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1 answer

CentOS 5 - hdparm - how to set DMA mode

I'm running CentOS 5 with a PATA hard drive. I've used hdparm to tune the hard disk for better performance, but there are 2 settings that don't work: hdparm -M 254 /dev/hda gives the error HDIO_DRIVE_CMD:ACOUSTIC failed: Input/output…
Tensigh
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tune2fs for f2fs

Is there a tool for editing (and viewing) the file system features for f2fs just like tune2fs for ext234? For instance you can get summarized info about the corresponding extX partition: # tune2fs -l /dev/path/to/disk To enable checksums on an…
user252842
3
votes
1 answer

Does dm-multipath schedule I/O?

I have a multipath device I'm interested in: [root@xxx dm-7]# multipath -ll mpathf mpathf (3600601609f013300227e5b5b3790e411) dm-7 DGC,VRAID size=3.0T features='1 queue_if_no_path' hwhandler='1 alua' wp=rw |-+- policy='round-robin 0' prio=130…
Bratchley
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0 answers

Tuning NFS: Identifying source of getattr requests

we run some Linux NFS clients against a NetApp NFS storage system. Currently we have over 50% getattr requests running against the NetApp using up precious CPU cycles. Using the netapp-top.pl script we identified the hosts causing high number of NFS…
Rainer Stumbaum
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1 answer

Where to get offline documentation/descriptions of individual sysctl kernel tunable parameters?

The NOTES section of $ man 5 sysctl.conf states: The description of individual parameters can be found in the kernel documentation. But is there a way for me to find this kernel documentation offline? Is it a package that I'd need to install? For…
Jethro Cao
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1 answer

CentOS 7 - When THP is disabled is it safe to ignore defrag setting?

I need to disable THP (Transparent Huge Pages). Many tutorials on the web advise to set never (0 for last one) value for below…
waste
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2
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1 answer

How can I create my own custom progress bar in Conky?

I have started using Conky some days ago, and I'm willing to create my own configuration. I have added some colors, cool ASCII art and learned the basics. However, I don't like the default progress bars coming with Conky, and I would like to create…
xvlaze
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1 answer

Memory Usage in Linux

How to setup limit for process to memory usage? Similar to open files limit in /etc/security/limits.conf: ubuntu soft nofile 4096 ubuntu hard nofile 8192 E.g. while I'm launching python script with raw…
youblind
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error: "net.inet.ip.fastforwarding" is an unknown key

I've been doing some research into improving performance for OpenVPN and I found out about setting fastforwarding to 1 but when I tried I got the error error: "net.inet.ip.fastforwarding" is an unknown key and tried error:…
Jason
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What's the best dirty_background_ratio and dirty_ratio for my usage?

So I'm playing with dirty_background_ratio and dirty_ratio and hoping to find the right parameters with your professional help. For now I'm using: vm.dirty_background_ratio = 20 vm.dirty_ratio = 60 The main usage is torrenting, that means that the…
Viktor
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How to find max limit of /proc/sys/fs/file-max

I am running Jenkins with lots of jobs which require lots of open files so I have increased file-max limit to 3 million. It still hits 3 million sometimes so I am wondering how far I can go. Can I set /proc/sys/fs/file-max to 10 million? How do I…
Satish
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is there any way to increase spawn rate of MinSpareServers in apache prefork

My server faces huge traffic only for short duration every day. And I don't want to waste my resource by running high amount of MaxSpareServers throughout the day. So, I would like to know is there any way to increase the spawn rate by the…
Siva
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slow/frozen ext4 // task sync blocked on big mostly write only server

We have several 90TB servers (Areca RAID-6 partitioned into 10 ext4 partitions) The application is basically a ring buffer; continuously writing data and deleting old data. As such, each partition is always 100% full (15GB per partition held as…
Danny
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