Questions tagged [performance]
The speed at which a program runs
1,043 questions
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dm-crypt IOPS amplification
I have a ZFS pool comprising a mirror comprising two partitions encypted with dm-crypt.
$ zpool list -v data2
NAME SIZE ALLOC FREE CKPOINT EXPANDSZ FRAG CAP DEDUP ...
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dd with 1M buffer is running at only 1 MB/s - disk usually can be accessed at full speed
I am running the command dd bs=1M if=/dev/zero of=/dev/md7 status=progress. It started very slow at 4 MB/s but now has dropped to 1 MB/s. This is a standard SATA disk that was running perfectly ...
- 101
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Why is my ZFS read performance tanking for RND4K reads and writes compared to an XFS partition on the same drive?
I have a pair of NVMe Crucial P5 Plus partitioned with an mdadm RAID1 partition formatted as XFS for / and another ZFS RAIDZ1 partition for the remainder of the disk.
Performance of the XFS partition ...
- 2,801
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how to configure or tune infiniband redhat 8
I asked a similar question here : NFS v4.2 tuning
with less than 50 servers on a closed infiniband [mellanox] HDR network switch all running RHEL-8.10:
is there anything other than systemctl start ...
- 8,271
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Recovery of a compressed image not possible due to lack of Space - general understanding of compression methods
I used gzip to compress an image which is quite huge still.
dd if=/dev/sda2 bs=1M | gzip -c -9 > sda2.dd.img.gz
then I changed the partitioning of the Drive because I wanted to install Linux.
And ...
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Disable read-ahead caching for GFS2 Logical Volume
I have 10 node deployment which implement red hat clustering software - pacemaker/corosync to mount gfs2 and ensure high-availability. Nodes are actually mail servers and use gfs2 to store user's data ...
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Should I use physical or logical sector size with LUKS?
I have an external HDD (not ssd) which reports:
Sector Sizes: 512 bytes logical, 4096 bytes physical
Should i use --sector-size 512 or --sector-size 4096 with cryptosetup LuksFormat? Using ...
- 620
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Scheduling priority on a kernel workqueue
In the kernel I can use the work queues and create them with alloc_workqueue(...) and pass it a flag WQ_HIGHPRI for a high priority workqueue.
I also see you can use apply_workqueue_attrs(...) for ...
- 284
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1
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Make parameter substitution in newline-separated string more efficient
The following code should demonstrate and help with testing inefficient Pattern Matching expressions in a Parameter Substitution for a newline-separated strings var vs. array.
The goal is to achieve ...
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Slow Linux file access to /tmp
time touch /tmp/test.dat
real 0m1.03s
user 0m0.00s
sys 0m1.02s
A full second of sys-mode time to create a file in /tmp. That can become unbearable for ksh scripts that open dozens of files ...
- 183
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sysfs missing CPU thermal_throttle information
Background Information:
I'm running Ubuntu 24.04.1 LTS (Noble Numbat, kernel 6.8.0-51-generic) on an AMD Ryzen 9 7950X3D, and I'm investigating some odd behavior where the CPU governor/driver will ...
- 11
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Transferring tar data between servers started taking much longer
I have a nightly backup that transfers about 100gb of data from AIX server A to AIX server B using the following command in a script.
tar cf - ./DATA | ssh server_b 'cd /DISKCOPY ; tar xf - '
This ...
- 11
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1
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NFS v4.2 tuning
https://www.youtube.com/watch?v=JXASmxGrHvY
at 5:30 the statement is made
if you get NFS tuned just right it is incredibly fast for ultra small file transfers*...
at 6:05
I've heard of 4.0GB/sec ...
- 8,271
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1
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How to determine what is opening tmp files when I invoke a subshell with ksh
I'm experiencing extremely sluggishness in opening subshells (by using ` ` or $( ) command substitutions in scripts) while in ksh on some Linux servers. The same problem does not exist in sh or any ...
- 183
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Speeding up curl in bash scripts
I'm using a Bash script to retrieve the Spotify album thumbnail from whatever I'm listening at the moment to show it as an image in Hyprlock.
For this particular case, I'm using the command curl to ...
