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Questions tagged [io]

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

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

401 questions
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What could cause Nginx to write this much I/O?

I have a high-traffic webserver (up to ~50 page loads per second) running nginx, which passes HTML requests to a PHP-FPM backend and serves static assets directly. Under this load, I get a curiously high amount of disk I/O from the nginx worker…
Manwe Sulimo
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Give read operations priority over write

I'm working on a system where I have a program that outputs high quality videos for a tv connected to an HDMI (raw 1080p data for instance) and I'm having an issue that when I copy some files to my hard drive it reflects on the FPS being displayed…
Lucas César
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Backup with rsync painfully slow

I'm using rsync to perform backups from an NFS server hosted in AWS to another EC2 instance in the same AZ, the rsync command that I'm using in the backup server is the following: rsync -avzb --backup-dir=someDirectory 172.19.0.151:/origin/*…
nikolaigauss
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What are the parameters in iostat

I used iostat and trying to understand the iostat output using this link : https://linoxide.com/linux-command/linux-iostat-command/ but It is not clearly explained. PF the output at different times from 18:00:00 to 18:45:00 : We got the delay in…
Harry
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How can I prevent high-volume filesystem writes from ovewhelming memory on my Linux system?

In several contexts, I've seen a behavior on Linux systems in which large volumes of filesystem write operations (e.g., many gigabytes of writes, very quickly) will overwhelm memory, apparently waiting for I/O operations to complete and buffered…
patbarron
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file system corrupt in a virtual machine

I have a virtual machine hosted by vmware esxi. It has been started for over 80 days. And about ten days ago, its file system got corrupted. Although I can use fsck to fix this file system, I am wondering what can be the root reason? It is just a…
Sraw
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How to check why a write failed?

If I was to debug a service on a machine and I determined that a write was failing, how could I check why the write failed? I know the system call in C will return -1 and then we can check what constant int errno contains (EINVAL,etc.). However, if…
screeb
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Google compute: Why persistent ssd disks are slower than persistent standard disks?

I ran several IO benchmarks and I cannot understand how pd-ssd offers a worse IO throughtput than pd-standard. In my tests I boot a VM with a bootable disk pd-ssd of 30 or 250GB, and I still get worse performance than with a pd-standard disk of…
Hector Fernandez
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A lot more write then read IO

As shown in the picture above we are having a lot more writes then reads on our appserver. Cache is enabled and the Framework is running with PHP/Symofony and using HTTP Cache. Is this I/O behavior normal? I doubt it, since with the cache the…
Isengo
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AWS EC2 snapshot reaches IOPS limit occasionally

For an EC2 server I have running I am creating a snapshot of the EBS every night. The EBS has 500GB of space and 1500 / 3000 IOPS. On some days past week the snapshot creating process reached it maximum IOPS causing the server to be unavailable for…
Bart Bergmans
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I/O scheduling on LVM on dm-crypt

I have the following setup: Stock Debian stable (Linux kernel 3.16.7) running on Dell PowerEdge R320 Two SATA hard drives in RAID1 on a PERC H310 Mini controller, visible as /dev/sda dm-crypt target dm-0 backed by /dev/sda2 A single LVM volume…
dragonroot
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NFS read/writes since startup

I'd like to retrieve the total number of kilobytes read/written for each NFS mount point. Using the following commands, I'm able to see the current throughput for each NFS mount point in kB/S. iostat -nk Alternatively: nfsiostat Is there a way to…
Fidel
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LXC (proxmox) JBD high (100%) IO utilisation

We have a dedicated server running a number of smaller guest VMs containing for example, HTTP server, MySQL and some real-time applications. However we find that JBD inside the guests are often spiking to 100% disk util approximately every 5-10…
JoshG
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Gentoo virt-manager IO throttling

I have a problem with virt-manager (or qemu/libvirt) installed on gentoo. Here is My virt-manager installed on Debian Jessie: There I have IO throttling but not on my Gentoo: I tried to search in google but I have not found nothing helpful on…
R.A.
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Why does SSHFS I/O latency test much faster than local RAID & NFS?

SSHFS tests for server I/O latency using dd returns very surprising results, so much so that I'm worried this might be some problem either with the test method or configuration. Test 1 on local RAID 10 disk using dd (512 bytes written one …
Pavin Joseph
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