Questions tagged [fio]
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22 questions
1
vote
1
answer
223
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Understanding `pgpgin` in `/proc/vmstat` as I/O Counters: Relationship with I/O Bandwidth Measurements
Hi Kernel I/O Experts,
I have a question regarding the pgpgin and pgpgout counters in /proc/vmstat, specifically focusing on pgpgin. I’ve been exploring performance monitoring tools like vmstat and ...
- 161
1
vote
1
answer
89
views
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 ...
- 558
0
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2
answers
1k
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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 1/0
...
- 839
11
votes
2
answers
2k
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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 ...
- 161
0
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1
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698
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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 ...
- 161
0
votes
0
answers
831
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 ...
0
votes
1
answer
459
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 ...
0
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1
answer
218
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
...
- 397
0
votes
1
answer
89
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?
- 965
0
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1
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120
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 ...
1
vote
0
answers
198
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 ...
- 31
3
votes
0
answers
1k
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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 ...
- 171
0
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2
answers
278
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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/...
3
votes
1
answer
1k
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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. ...
- 776
0
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0
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1k
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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 ...
