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Questions tagged [io]

IO (or I/O) is an abbreviation for input/output, most commonly referring to disk input/output.

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High IO utilization without high read/write

Our server occasionally becomes laggy when writing files. using iostat I noticed that the disk utilization is abnormally high. However, the read/write per second does not seem too high # example ...
ZeroRin's user avatar
  • 13
0 votes
1 answer
149 views

Why Swap usage is high for Influxdb: 100% Disk I/O and Swap usage but only 50% memory?

We have an influxdb VM that is constantly under 100% swap. Even if we restart the VM, the swap usage reaches 100% in about 20 minutes. However, memory usage is only about 50%. (The VM has 32 CPU Cores ...
Vipin Menon's user avatar
2 votes
0 answers
69 views

How useful is ionice tool with modern linux kernel

Ionice tool is supposed to offer relieve on high I/O load by executing commands only when system is in specified state. https://www.linux.org/docs/man1/ionice.html states Linux supports I/O ...
Darko Miletic's user avatar
1 vote
0 answers
170 views

dmesg spamming "Power-on or device reset occurred"

So I have a DELL R730xd Server with 24 SSDs on a PERC H730P Mini controller in HBA mode. All 24 drives are in one big ZFS Raid-Z2 pool. I have noticed that dmesg gets spammed with a lot of these ...
FloatingPointOperation's user avatar
19 votes
2 answers
3k views

What could explain unknown I/O on new 16TB HDD on a Debian server?

I recently obtained a new 16TB HDD for my Debian server. I first created a partition (gpt) on it via my Ubuntu-like desktop, formatted it (ext4), and rsync'ed old data on it. The disk is now usable, ...
b4too's user avatar
  • 193
1 vote
0 answers
436 views

MariaDB io_uring_queue_init() failed with errno 1 with kernel version 6.2.0-1018

I am running MariaDB using the official docker hub image: mariadb:lts (this is MariaDB 10.11.6-MariaDB-1:10.11.6+maria~ubu2204 source revision fecd78b83785d5ae96f2c6ff340375be803cd299) When the ...
g.pickardou's user avatar
2 votes
0 answers
116 views

Disk I/O over 100% (~400%)

I'm working with an Ubuntu OS cluster which is using a Job scheduler. Tens of jobs are running in parallel and all jobs read/write in the same disk Array, 3 SSD disks with software RAID 0. I do not ...
Emma Athan's user avatar
0 votes
0 answers
455 views

SSIS package cannot see network drive

I have an SSIS package that cannot see a network folder (with files) - when run directly from SSMS. (Windows Server 2019, SQL Server 2019, Visual Studio 2019, SSMS versions 17 & 18). I am using a ...
Clinemi's user avatar
  • 101
5 votes
1 answer
223 views

Unable to get my rsync of my software RAID 6 past 40MB/s. Looking for suggestions

Wondering what I could adjust to get my RAID 6 Software Raid to resync quicker. Currently it's proceeding at max of 64MB/s and averages to something around 25MB/s. Hoping to get it to 200MB: [...
DeliciousBoulder's user avatar
0 votes
0 answers
244 views

Memory mapped files filesystem access over NFS performance

I'm debugging a system that is accessing files on AWS EFS, where the EFS reaches is peak throughput because of IO operations. I noticed that the application is sometime reading memory mapped files in ...
yogi's user avatar
  • 101
1 vote
1 answer
77 views

Disk saturated by mariadb on CentOS 7, blocks everything

For the past few days I have been having a problem with a webserver running CentOS 7. Every 13-14 minutes some operation (which I identified with mariadb using iostat) seems to completely saturate the ...
Gregorio Pellegrino's user avatar
9 votes
1 answer
902 views

Finding which process is reading from disk constantly on FreeBSD

EDIT: This ended up being a scrub process. Run zpool status -v and read the scan status for your pool clearly. I have a TrueNAS server running FreeBSD and this morning at 12 AM the disks started to be ...
Bilbo Baggins's user avatar
0 votes
1 answer
340 views

ZFS I/O Error, Kernel Panic during import

I'm running a raidz1-0 (RAID5) setup with 4 data 2TB SSDs. During midnight, somehow 2 of my data disks experience some I/O error (from /var/log/messages). When I investigated in the morning, the zpool ...
Jealous_Donut_7128's user avatar
0 votes
0 answers
500 views

I have a new server but IO Speed is terrible based on FIO results

I ordered a new server because I have to move to higher performance server. However, this new server is totally awful. I tried to get the benchmark by using fio here is the result. [root@s206716 ~]# ...
James Hartford's user avatar
1 vote
0 answers
46 views

iotop PRIO column is showing ?sys

How can i fix iotop to show PRIO correct value?
CrazyRabbit's user avatar
1 vote
1 answer
365 views

Strange IO activity

I have some strange IO activity on a server and I can't figure our where it's coming from. To provide some background, I had to replace an NVMe (Samsung PM81) from a server due to wear. I didn't ...
Alexandre Ramírez's user avatar
0 votes
2 answers
710 views

High iowait, swap nearly always fully in use

I'm often experiencing slowness on a large server that is used by several users simultaneously, with many CPUs (72) and a decent amount of ram (125gb). Granted, the server runs a lot of stuff so gets ...
dreamer's user avatar
  • 101
2 votes
1 answer
3k views

Weekly RAID check affecting my system - any way to mitigate?

I recently got my webhost (Hetzner) to add a paid of 16TB SATA drives to my webserver. Currently using 2.5TB of them. They're RAID 1 mirrored. I also have two 4TB nVME drives with 700GB currently on ...
Codemonkey's user avatar
  • 1,148
0 votes
1 answer
330 views

Does my swapping server with ~80GB available RAM need even more?

I'm administering a Debian Linux x86_64 server with 125GB RAM, a 10GB swap partition and a swappiness value of 60. A free -gw output prints: total used free shared ...
eheu's user avatar
  • 3
0 votes
0 answers
397 views

Centos stream 9 local console login input shown as squares

I'm after a fresh centos stream 9 install as minimal install, with only English keyboard and only root user. After installing, I rebooted and got to the login screen. Trying to type "root" ...
Harry Zalessky's user avatar
0 votes
0 answers
502 views

High I/O wait in apache tomcat server

Facing high I/O wait in apache tomcat server when the load increases. Suspecting disk I/O is less when tomcat is running however. disk IO seems drops drastically when tomcat is running along with the ...
Sandesh Bailur's user avatar
1 vote
0 answers
92 views

Couchdb 3.1.1 increases disk latency gradually over weeks

I've been dealing with this issue for weeks now. I have the followin scenario: couchdb2.3.1-A <===> couchdb2.3.1-B <===> couchdb3.1.1-A <===> couchdb3.1.1-B where <===> ...
Roberto Iglesias's user avatar
0 votes
1 answer
2k views

Testing zpool IO performance

To test the write speed of a 2.5 inch SATA3 spinning hard drive (some old Seagate one) installed in my TrueNAS system I used dd if=/dev/zero of=/mnt/pool/test.dd bs=1024 count=1m (found this in ...
Andept's user avatar
  • 73
2 votes
2 answers
1k views

Dmesg is full of I/O errors on Ubuntu 18.04 VM, physical disks and host are fine

I have an Ubuntu 18.04 virtual machine on a Windows Server 2016 host (Dell PowerEdge R530, Intel Xeon E5-2620 @ 2.1GHz, 96GB RAM), running in VirtualBox 6.1.10. The host system has 2x2TB HDDs in RAID ...
Marcell Bernát's user avatar
-1 votes
1 answer
537 views

Simulate some process IO with fio or other tool

Is there any way to track a specific process and get stats for disk IO such as queue depth, total reading/writing threads, percent of reads/writes and so on? The main goal is to use all that ...
Maxim's user avatar
  • 105
1 vote
1 answer
854 views

Interpreting SMART Logs of Newly Installed NVMe RAID0 Crashing Everyday

An Ubuntu 20.04 system has been stable for a year until a 2nd and 3rd NVMe drive is installed on the motherboard to form a 2x1TB RAID0 array. Ever since then, there is huge amount of IO load on this ...
Nyxynyx's user avatar
  • 1,489
0 votes
0 answers
181 views

Getting high read await in Zabbix monitoring, is this a common behavior for RAID5 disk array?

We are running a Oracle 11.2 DB on Redhat 6.8, and disk array is configured as RAID5, which is using a Lenovo 730i RAID adapter. I checked RAID policy and found that "Read Ahead Always" and &...
Jason Yang's user avatar
2 votes
0 answers
2k views

kvm virtualization, slow io in windows guest (with virtio drivers) on ubuntu host and HP 360 Server with P440 RAID controller

Problem: Very slow IO in Windows Guest vs Host Hardware: HP 360 G9, 2 x 10 cores Xeon CPU, 128GB Ram, 4 x 4TB SAS HDD, Raid 10, P440 Controller (with 2GB cache and battery) Host: Ubuntu 20.04 Server, ...
Enovator's user avatar
0 votes
1 answer
1k views

disk read io very high, but no process perform io read

We have experienced a very strange problem. The load of the server machine is very high due to high disk read io. But the processes running on this server do not perform any disk read operation. We ...
yifan's user avatar
  • 163
2 votes
1 answer
525 views

About IOPS of a RAID5 disk array without cache

we are using a 530-8i RAID adapter,which is none-cache supported, on a Lenovo ThinkSystem SR590 server.And we have 4 HDD(600GB/10K RPM/SAS) in the array. I read an article about calculating the disk/...
Jason Yang's user avatar
0 votes
1 answer
262 views

It is possible that a process can not link a file, but I can with sudo for the same user?

I am working with Dovecot 2.3.4.1 and EncFS (encfs version 1.9.5) encrypted mailboxes on Debian 10 (no SELinux) Basic setup is: EncFS mounted with encfs --public /var/encrypted-mail /var/decrypted-...
func0der's user avatar
  • 164
2 votes
0 answers
863 views

Access disk io data in linux without tools like iotop/iostat to find processes or files with IO

We have regularly high load average. With the help of a zabbix agent, I could narrow it down to be mainly because of cpu iowait (and lastly disk io). I am not allowed to install any additional ...
nox's user avatar
  • 121
0 votes
1 answer
207 views

ZFS raidz3 on proxmox having IO issues

I'm running Proxmox 6.2-11 with 256GB ECC RAM and the following raidz3 pool: pool: rpool state: ONLINE scan: scrub repaired 0B in 0 days 15:25:14 with 0 errors on Sun Jan 10 15:49:29 2021 config: ...
Stanimir Stoyanov's user avatar
0 votes
0 answers
371 views

High %wa from top command while runing PyTorch

Everything was fine yesterday, but I noticed high dataloading time this morning. How do I go about trying to figure out how to fix this? top: process state: iotop: iostat:
Prior Lee's user avatar
0 votes
1 answer
142 views

Does add more memory RAM decrease I/O wait?

My server is Ubuntu KVM and has 2 cores, 4GB RAM, and I use HDD, at moment I can't swap HDD to SSD. I found this answear (https://unix.stackexchange.com/a/463819/351968) saying that adding more memory ...
mario's user avatar
  • 155
-2 votes
1 answer
47 views

SSD I/O slows down system

My HDD was getting full, so I added a new SSD and tried moving files to it. For some reason, this bogs down the whole system to the point where it's not usable. This never happened with HDDs when ...
david's user avatar
  • 101
2 votes
1 answer
1k views

Looking for a NBD C/S for windows (Network Block Device) [closed]

Where can I find a NBD Server (and also a Client) that I can use in windows 10? (preferably FOSS source code for inspect/change/compile/...) Been looking for a while on the internet and seems that no ...
ZEE's user avatar
  • 336
0 votes
1 answer
343 views

Is RAID 6 a good choice regarding performance on server used for computation?

We are operating a server for doing computations with large data sets (100GB - 5TB) for a small group of researchers (10-20 people). At the moment we are running 4x8TB spinning drives in a RAID 6 ...
lumbric's user avatar
  • 244
0 votes
1 answer
413 views

Fio brandswitch measure

In disk benchmarking tool fio there is statistics for brandswitch Run status group 0 (all jobs): READ: bw=20.9MiB/s (21.9MB/s), 10.4MiB/s-10.8MiB/s (10.9MB/s-11.3MB/s), io=64.0MiB (67.1MB), run=...
ogbofjnr's user avatar
  • 193
2 votes
1 answer
111 views

MYSQL vs. InnoDB [closed]

mysqltuner output. -------- Storage Engine Statistics ----------------------------------------------------------------- [--] Status: +ARCHIVE +BLACKHOLE +CSV -FEDERATED +InnoDB +MEMORY +MRG_MYISAM +...
Nasir Mahmood 's user avatar
1 vote
0 answers
179 views

disk I/O latency spikes (contains log files from amplify)

Ubuntu 18.04 LTS server, disk is ssd. Application stack is: mongodb, node, nignx and some python. Server is up 1 month and already had 3 OS disk fails where Ubuntu would go in read only mode. After ...
usernumber124153's user avatar
0 votes
0 answers
282 views

What are the best practices for device-mapper multipath?

Background: We are setting up the new storage for an HPC Compute cluster for applied statistics, bioinformatics, and genomics. Contrary to our expectations, an active-active configuration did not ...
Nicolas De Jay's user avatar
4 votes
2 answers
1k views

Use F2FS on RAID0 within HDD?

My server contains 128 monitors and that caused many random write IO be submitted. If I use SSD, many writes will make it broken soon. I read some articles about F2FS and know it works better on flash ...
code_worker's user avatar
1 vote
1 answer
665 views

Low performance on file copy operations due large idle times (rsync, cp, ..)

I'm currently copying large directory tree from an external HDD to to internal storage of my server. The performance of the copy operation is basically quite good, i.e. 35MB/s with the external HDD ...
PraMiD's user avatar
  • 11
1 vote
0 answers
146 views

Mysterious, intermittent Read I/O on Ubuntu 18.04 based EC2 server - iotop shows no disk reads

I have an EC2 server based on Ubuntu 18.04. With CloudWatch detailed monitoring enabled I'm seeing spikes of Disk Read Operations that last less than 1 minute (shown as 1-minute spikes on the graph) ...
janoside's user avatar
  • 111
1 vote
0 answers
304 views

PHP high I/O after a DDoS attack

I've had a large scale DDoS attack on my website. After I've enabled captcha challenge through CloudFlare and the attack stopped, PHP's I/O was still loaded at 99%, and the website was working very ...
HTMHell's user avatar
  • 183
1 vote
0 answers
784 views

How does avgqu-sz size in iostat output relate to r_await and w_await?

Can someone explain what does avgqu-sz mean in the output of iostat? The manual page states like this. avgqu-sz: The average queue length of the requests that were issued to the device. Can ...
tuk's user avatar
  • 343
0 votes
1 answer
114 views

cat an file programs fail to acess a file but vi works properly (Debian)

I have getting some problems with my system after a bad reset via ctrl+alt+del. Since then errors related to ACPI and ata6 are reported. Trying to get a solution to this (in a savage way:I am n00b), I ...
Daniel Bandeira's user avatar
1 vote
0 answers
1k views

Huge IO performance degradation between proxmox ZFS host and WS19 VM

For more than a week, I am trying to determine the reason for the following IO performance degradation between proxmox host and a Windows Server 2019 VM(s). I have to ask for your help guys because I'...
Programmierus's user avatar
3 votes
5 answers
4k views

Linus/ext4/nvme crashes during high io

During mvn compilation, I have random crashes. The problem seems related to high IO and in kern.log, I can see things like: kernel: [158430.895045] nvme nvme1: controller is down; will reset: CSTS=...
Brimstedt's user avatar
  • 151

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