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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.

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Acceptable I/O speeds for 6 x 250GB SSDs in RAID 10

I'm running CentOS 7 (XFS filesystem) on a dell server with a PERC H700 raid controller. Inside this server I have 6 x Samsung 850 Evo 250GB SSDs (yes they are consumer drives however, this is a home server. In any case, I performed a DD test and am…
FriendlyBystander
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Windows Server 2012 with SSD local drives -- Random or Sequential I/O?

How can I determine where my Windows Server 2012 is using Random or Sequential I/O operations when writing/reading the local SSD storage? I have been asked to provide details to our hardware vendor on server usage in order to performance tune the…
Geoff Dawdy
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How to save iotop's output for a specific period of time

I am trying to discern what processes are making huge Read/Writes on my server disk. I know I can use iotop -ao but is there a way I can save iotop's output for a specific period of time to study later?
developer
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How can I measure complex I/O activity to develop realistic benchmarking?

I need to retrieve a few metric from my service server to benchmark another stroage solution. There are various options are provied by benchmark program(I choosed FIO,http://freecode.com/projects/fio). I could easily set up io pattern with it. But I…
jinhwan
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High iowait for unknown reason

I'm having a hard time figure out the reason cause high iowait on my server. This is log of iostat -xm 5 5 Linux 2.6.32-358.6.1.el6.x86_64 (prod-1.localdomain) 09/28/2013 _x86_64_ (16 CPU) avg-cpu: %user %nice %system %iowait %steal …
favadi
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iotop does not show writes

What could be writing on the disk that iotop does not show? # iotop -a Total DISK READ: 8.19 M/s | Total ****DISK WRITE: 3.34 M/s**** TID PRIO USER DISK READ DISK WRITE> SWAPIN IO COMMAND 428 be/4 root 0.00 B 84.00 K …
Marki
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Reduce the I/O priority of Windows Backup (Windows Server 2008 R2)

I have a PostgreSQL running on Windows Server 2008 R2 x64 box. And I have scheduled a backup everyday from the RAID 1 DB disk to a dedicated standalone disk. They are SAS 15k on Dell PERC 6i. I am using the built-in Windows Server Backup for…
HelloSam
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Issues with Server 2012 using DFSR running on Hyper-V 2012

We have a number of Server 2012 systems, all of which run virtualised on Hyper-V 2012 server. We are having problems with two such virtual instances, both of which are used as file servers, whereby they occasionally stop responding to requests to…
Bryan
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In Windows Task Manager, in the Processes tab, what does I/O Other mean?

In Windows Server 2003, I'm seeing a process in Task Manager with a high value in the I/O Other column. I'm trying to determine if it's in some kind of error state, but I don't know what I/O Other means. I/O Reads and Writes are low. What is I/O…
Barry B
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Will adding a SSD cache device to my ZFS storage improve performance?

The server has 4GB of RAM and my zpool is made up of 15.5k SAS drives arranged like this: NAME STATE READ WRITE CKSUM tank ONLINE 0 0 0 raidz1-0 ONLINE 0 0 0 c0t2d0 ONLINE…
Sysadminicus
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How do I tell which processes are writing heavily to disk in CentOS 5?

Our server started getting slow, so I ran iostat on it. iostat -dx 5 Device: rrqm/s wrqm/s r/s w/s rsec/s wsec/s avgrq-sz avgqu-sz await svctm %util sda 0.00 89.60 108.40 5.60 880.00 763.20 14.41 …
Artem
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Linux Read-Ahead Downsides

Are there any downsides to raising the size of the read-ahead cache? On our farm, we're currently running at 256, and upon raising that higher, we are seeing significant throughput gains.   [root@server~]# hdparm -tT /dev/sda /dev/sda: Timing…
JPerkSter
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What units are the I/O measures in GNU "time" in?

GNU time has optional display of I/O measurements: TIME="%I:%O" /usr/bin/time cp filea fileb 0:5488 but what units is it measuring? Any ideas? The manual only says %I Number of filesystem inputs by the process. %O Number of…
Craig Ringer
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Mariadb 10.3 high disk write rates

With the help of some other fine people here, I have found the high loads we have been experiencing lately are related to mysqld high disk write rate seen in iotop. With a load average now 3-6 where it used to stay around one. I installed mytop to…
rwfitzy
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Troubleshooting `Buffer I/O error` on software-raid/md-device

I've got a RAID-5 mdadm array that reliably causes Buffer I/O error on dev md0, logical block 1598030208, async page read to be written do dmesg when reading that block. Of course, the read also factually fails. This behavior is consistent across…
RQM
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