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Diagnose bash autocomplete issues

I have one binary on my system, fio installed via package manager which doesn't autocomplete files with tab once you've typed fio . I guess this means something must over overridding the autocomplete ...
BeeOnRope's user avatar
  • 559
0 votes
1 answer
122 views

io_uring with `fio` fails on Rocky 9.3 w/kernel 5.14.0-362.18.1.el9_3.x86_64

I've tried various variations of the command: fio --name=test --ioengine=io_uring --iodepth=64 --rw=rw --bs=4k --direct=1 --size=2G --numjobs=24 --filename=/dev/sdc lower queue depth direct set to 1/...
Grant Curell's user avatar
0 votes
0 answers
126 views

Understanding I/O Depth in **Output** of Fio for performance insights

I've been using libaio to benchmark the IOPS of an NVMe SSD, and I've noticed an interesting observation in the output regarding IO submit and IO complete. (Note that I am not asking about the fio's ...
JGL's user avatar
  • 147
11 votes
2 answers
1k views

Differences Between `/dev/null` and Devices Under `null_blk` Driver

I recently encountered the Linux Null Block device driver, null_blk, while I benchmarking the I/O stack instead of on a specific block device. I found the devices created under this driver (let's use ...
JGL's user avatar
  • 147
0 votes
1 answer
276 views

FIO reports slower sequential read than the advertised NVMe SSD read bandwidth

TLDL For the very simple sequential read, FIO reports is much slower than the NVMe SSD sequentail read capability. Main Text Hello everyone, I have been facing an issue while trying to achieve the ...
JGL's user avatar
  • 147
0 votes
0 answers
587 views

understanding fio test results - 90th percentiles benchmark - Latency --> avg/stdev?

What are the relationships in storage benchmarking with fio between the average(avg) and standard deviation (stdev) at latency? Avg / stdev at latency is important for sequential or random test? Most ...
Hamza Karabulut's user avatar
0 votes
1 answer
249 views

How does the --bsize option in fio work?

Since fio is a benchmarking tool that for each run, should simulate a real I/O workload, how does the --bsize option fit with that? My understanding is that the filesystem has a set block size for ...
Macondoman's user avatar
0 votes
1 answer
178 views

Why Disk stats show many read operations when I measure NVME squance write with fio and mmap as ioengine

Here is my fio configure and report: # cat fio-write.fio [global] name=fio-seq-writes filename=test rw=write bs=1M direct=0 numjobs=1 [file1] size=1G ioengine=mmap iodepth=1 # fio --version fio-3.30 ...
Chen Li's user avatar
  • 387
0 votes
1 answer
73 views

Doing fio testing and hotplug remove the SSD

When disk is in use, ex: doing fio testing ( random write ), remove the PCIe SSD at the same time. Should I expect there is no any I/O error since the system support hotplug?
Mark K's user avatar
  • 895
0 votes
1 answer
98 views

RAMDisk disappears after random read tests

I have created 60GB RAMDisk using the command modprobe brd rd_size=62914560. It creates 16 RAMDisks and I use /dev/ram1. The linux is CentOS 7.5 with kernel version 3.10. I don't make any filesystems ...
Arghavan Mohammadhassani's user avatar
1 vote
0 answers
131 views

FIO processes go from aiospn to 100% CPU

I'm using FreeBSD 12.2 and FIO 3.24. The ioengine parameter is posixaio. Testing NVMe drives. During the initial part of our testing, we hit the unit under test with a QD of 32 and numjobs of 4 for 3 ...
jim feldman's user avatar
3 votes
0 answers
1k views

Extremely poor performance for ZFS 4k randwrite on NVMe compared to XFS?

I've been a fan of ZFS for a long time and I use it on my home NAS, but in testing its viability for production workloads I've found that its performance is inconceivably bad compared with XFS on the ...
Evan's user avatar
  • 171
0 votes
2 answers
248 views

Multiple Threads Cannot Access the Same RAMdisk Created by modprobe

I have created RAMdisks of 60GB using modprove brd rd_size=62914560 on CentOS 7.5. Checking the results, fdisk -l /dev/ram* shows 16 ram block devices of 60GB size (/dev/ram0, /dev/ram1, ..., /dev/...
Arghavan Mohammadhassani's user avatar
3 votes
1 answer
782 views

Does it make sense to use queue-depth when doing synchronous IO benchmark?

Does it make sense to have a queue depth > 1 when doing a synchronous IO benchmark? I was expecting the same result a of QD1, but QD32 does give better result? I thought it would just be ignored. ...
MrCalvin's user avatar
  • 699
0 votes
0 answers
1k views

Understanding "Laying out IO file" in fio

I am trying to understand what really happens when in the "Laying out IO file". I have btrfs installed on a raw block device and whenever I run fio with the following configuration, I see ...
linux_engine's user avatar
0 votes
1 answer
321 views

What makes completion latency various in Fio benchmark with NVMe SSD?

I'm trying to figure out the completion latency of fio benchmark with NVMe SSD. I made following fio script to test benchmark in fio. I used following options. rw=read, ioengine=sync, direct=1 So, I ...
ray5273's user avatar
1 vote
1 answer
64 views

Quickly assemble raid5 for perf test

I'd like to run a series of fio-based performance tests on a few drives in various RAID and non-RAID configurations. When assembling drives in RAID5, the rebuild process takes an incredibly long time (...
Huckle's user avatar
  • 1,025
0 votes
1 answer
2k views

fio: how to test for bs less than 1 filesystem-block size?

I am testing my SSDs and have two questions. SNIA has published specification PTS (SNIA) to test SSD . In many cases, it requires device to be tested for bs=0.5Ki !! What is the rational behind this? ...
user3488903's user avatar
1 vote
1 answer
263 views

How does a utility 'fio' perform VFS like operations on raw unformatted devices with no filesystem on them?

I understand that one cannot do VFS operations on a medium with no filesystem. Given that, how does a utility like fio perform VFS-like read/write/seek operations on raw devices?
nishad kamdar's user avatar
0 votes
1 answer
326 views

fio: how to write 2X user capacity?

My system has SSDs and I wanted to run some benchmark tests on it based on SSS PTS (SNIA). For example, for IOPS test, the spec suggested to use QD=32, TC=4 and for doing IO, the spec says following. ...
user3488903's user avatar
1 vote
1 answer
846 views

fio: how to reduce verbosity?

When I run fio command, I get huge file with following lines which fills up the entire space. I am interested in only the final fio output summary. How can I reduce this fio verbosity? :::: Jobs: 4 (f=...
user3488903's user avatar
1 vote
2 answers
1k views

Why is overwiting a file slower than writing to a new file?

I noticed that sequentially overwriting an existing file may be much slower than writing a new file. Example: mkdir del cd del fio --name=seqwrite --rw=write --ioengine=sync --bs=128KiB --size=10GiB ...
maxschlepzig's user avatar
  • 57.9k