Questions tagged [performance]
The speed at which a program runs
1,043 questions
2votes
0answers
38views
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 ...
- 1,301
0votes
1answer
45views
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
1vote
0answers
31views
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 ...
- 2,811
0votes
1answer
28views
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 ...
- 8,301
2votes
2answers
68views
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 ...
0votes
0answers
19views
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 ...
1vote
1answer
58views
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
1vote
0answers
64views
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
2votes
1answer
104views
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 ...
3votes
0answers
83views
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
1vote
0answers
53views
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
1vote
0answers
63views
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 ...
0votes
1answer
202views
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 ...
- 8,301
5votes
1answer
303views
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
0votes
1answer
72views
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 ...
