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Questions tagged [fio]

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17 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 ...
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0answers
19 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 ...
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0answers
95 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 ...
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0answers
30 views

FIO shared iodepth

I'm trying to write an FIO test to simulate mixed read/write activity in a certain way. This is what I'm trying to simulate: Write task: Fill a queue of iodepth with write I/O requests. Read task: ...
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2answers
65 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/...
1
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1answer
76 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. ...
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0answers
201 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 ...
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1answer
40 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 ...
1
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1answer
21 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 (...
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1answer
591 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? ...
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1answer
30 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?
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1answer
66 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. ...
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votes
1answer
117 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=...
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2answers
195 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 ...