Linked Questions

6
votes
4answers
6k views

Is it necessary to have RAID in a virtual machine?

I have a Windows 2008 Enterprise on RAID 10 running Active Directory, Hosted Exchange, and a web server on HyperV VMs. Do I need a virtual RAID for Exchange? If so, why? Edit: thanks everyone for the ...
7
votes
3answers
16k views

Understanding RedHat's recommended tuned profiles

We are going to roll out tuned (and numad) on ~1000 servers, the majority of them being VMware servers either on NetApp or 3Par storage. According to RedHats documentation we should choose the ...
9
votes
4answers
9k views

Suggestions for making sysfs parameters persist across reboots

I'm experimenting with large changes to Linux system runtime parameters exposed through the sysfs virtual file system. What is the most efficient way to maintain these parameters so that they persist ...
4
votes
7answers
5k views

How to tell if linux disk IO is causing excessive (> 1 second) application stalls

I have a Java application performing a large volume (hundreds of MB) of continuous output (streaming plain text) to about a dozen files a ext3 SAN filesystem. Occasionally, this application pauses for ...
8
votes
6answers
1k views

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. ...
7
votes
1answer
6k views

HP DL380 G7 + Smart Array P410i + sysbench -> poor raid 10 performance

I have running system with low IO utilization: HP DL380G7 ( 24gb RAM ) Smart Array p410i with 512mb battary backed write cache 6x SAS 10k rpm 146gb drives in RAID10 Debian Squeze linux, ext4 + LVM, ...
9
votes
2answers
3k views

CentOS 6 doing lots more IO than CentOS 5

I'm benchmarking an application on two identical servers, one is Centos 5.8 and the other is Centos 6.2. My application is running much slower (50% or less) on the Centos 6.2 machine. In attempting ...
3
votes
3answers
7k views

HP P410 RAID + Samsung 830 SSDs + Debian 6.0 - What performance to expect?

I'm renting two dedicated servers from a hosting company. Here are the specs: server1: HP ProLiant DL165 G7 2x AMD Opteron 6164 HE 12-Core 40 GB RAM HP Smart Array P410 RAID controller 2x Samsung 830 ...
2
votes
2answers
11k views

Determining cause of high NFS/IO utilization without iotop

I have a server that is doing an NFSv4 export for user's home directories. There are roughly 25 users (mostly developers/analysts) and about 40 servers mounting the home directory export. ...
3
votes
5answers
497 views

Array on servers which receive several hundred GB of data a day

This is hopefully a simple question. Right now we are deploying servers which will serve as data warehouses. I know with RAID 5 the best practice is 6 disks per RAID 5. However, our plan is to use ...
2
votes
2answers
1k views

What are front merges in I/O scheduling and how can I tune this parameter?

My Linux uses the Deadline algorithm for I/O scheduling. One of the parameters is the front_merges parameter under /sys/block/sda/queue/iosched/front_merges. By default it is set to 1, which means ...
3
votes
4answers
2k views

How can I reduce inode utilization on an ext4 filesystem?

Summary of My Need We put a large amount of files on a filesystem for analysis at a later time. We can't control how many files we're going to have, and this one box needs access to all of them. ...
2
votes
3answers
2k views

SNMPD running but not listening for connections at random

OS: CentOS release 5.7 (Final) Net-SNMP: net-snmp-5.3.2.2-14.el5_7.1 (from RPM) Periodically my NMS notifies me that SNMP has gone down on this machine. The service is restored in between 10 to 30 ...
1
vote
2answers
3k views

RHEL optimization for write-intensive disk operations

What configuration optimizations e.g. disk scheduling algorithms are suggested for a very write intensive setup ?
2
votes
2answers
1k views

Running “find” command generates high load

I run this command on a Debian server with SSD drives configured as RAID 1: ionice -c 3 find . -type f -amin -1440 -mmin +1441 -not -path custom/ -print0 on a path which contains over 1.7M files and ...

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