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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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5.5GB written daily to 1.2GB root volume - 4 times previous levels

Problem: I recently revamped one of my servers, it was tested prior to use, and functions well, however, a few days ago, I noticed approximately 4 times the usual amount of writes to the root volume. This is not a performance issue - the server runs…
cyberx86
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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 read from constantly. I thought this was some…
Bilbo Baggins
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Dmesg full of I/O errors, smart ok, four disks affected

I'm working on a remote server (Dell Poweredge) that was a new install. It has four drives (2TB) and 2 SSD's (250 GB). One SSD contains the OS (RHEL7) and the four mechanical disks are eventually going to contain an oracle database. Trying to…
Scu11y
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what is the relation between block size and IO?

I have been reading about disk recently which led me to 3 different doubts. And I am not able to link them together. Three different terms I am confused with are block size, IO and Performance. I was reading about superblock at slashroot when I…
Ankit Kulkarni
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rrdgraph generation fails on high IO load

We have a 4 core CPU production system which does a lot of cronjobs , having constant proc queue and an usual load of ~1.5. During night time we do some IO intensive stuff with postgres. We generate a graph showing the load/memory usage…
Dennis Nolte
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How to keep subtree removal (`rm -rf`) from starving other processes for Disk I/O?

We have a very large (multi-GB) Nginx cache directory for a busy site, which we occasionally need to clear all at once. I've solved this in the past by moving the cache folder to a new path, making a new cache folder at the old path, and then rm…
David Eyk
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Flush-0:n processes causing massive bottleneck

I have a LAMP cluster that shares files via NFS and occasionally one of them will be stricken for a while when mysterious flush processes start appearing. Can anyone help me? The only way to resolve this is to reboot - killing the processes only…
Tom
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6 answers

Linux I/O bottleneck with data-movers

I have a 24 core machine with 94.6GiB RAM running Ubuntu server 10.04. The box is experiencing high %iowait, unlike another server we have (4 cores) running the same types and amounts of processes. Both machines are connected to a VNX Raid…
Benjamin
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Can I run iostat on a Synology?

I have a Synology RS812RP+ which I'm using for a little bit of departmental testing. I've stuffed a bunch of SSD disks in it, and I'm curious about monitoring the disk IO. iostat doesn't come pre-installed on the synology and it doesn't have the…
Zorlack
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using temporary files vs pipes advantages and disadvantages

Say I have a file named jobs.csv and I would like to get the top 50k jobs done by Foo I can either do: # cat jobs.csv | sort -u | head -n 50000 > /tmp/jobs.csv # cat /tmp/jobs.csv | while read line; do Foo --job=$line; done Or # cat jobs.csv | sort…
Tzury Bar Yochay
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3 answers

What program in Linux can measure I/O over time?

I'm trying to measure the total amount of disk writing and reading that is done to a particular volume by a particular process over a specified duration. I've found iotop, which can output IO every second for a particular process like this: iotop…
Neil
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How efficient is the tac command on large files

The taccommand (catreversed) can be used to read a file backwards, just like cat reads it rom the beginning. I wonder, how efficient this is. Does it have to read the whole file from the beginning and then reverses some internal buffer when it…
Daniel Schneller
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Linux - KVM - very slow disk io

The I/O performance of my new server is pretty low. I Googled and tried everything I can imagine. First of all, here are the Hardware Components: AMD Opteron(tm) Processor 6344 4x Seagate ST3000VX000 Its currently running on a software…
T-Bash
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Identify which process is responsible for heavy disk i/o under FreeBSD

I wonder how I can monitor which process takes out all my IO bandwith. The only command i know is gstat but it shows cumulative info. Is there any tools i can use to inspect the running processes for their io usage? The system is FreeBSD 8.3 Thank…
Sergey Efimov
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Is a 'high' IO rate healthy?

I do a lot of work with my Linode that currently hosts a site, but every now and then (usually once every two months or so) - I'll get a warning about my IO rate being too high (Usually just higher than 6000). The last one I got said: "Your Linode…
user82250
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