Questions about server hardware and software performance, or network performance.

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0
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1answer
2k views

GlusterFs - high load 90-107% CPU

I try and try and try to performance and fix problem with gluster, i try all. I served on gluster webpages, php files, images etc. I have problem after update from 3.3.0 to 3.3.1. I try 3.4 when i ...
-1
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0answers
20 views

Two small VPSs or one bigger VPS? [duplicate]

I have a relatively busy WordPress site (http://ndsmcobserver.com). I'm currently on Linode 2GB plan, but performance is pretty sluggish, especially when performing searches and working every night ...
3
votes
4answers
6k views

Howto check disk I/O utilisation per process

Im having a problem with a stalling Linux system and I have found sysstat/sar to report huge peaks in disk I/O utilization, average service time as well as average wait time at the time of the system ...
3
votes
1answer
29 views

iozone: 5 concurrent threads random read of 300K blocks does more ops/s than using only one thread, what could be the underlying reason?

The partition is in RAID1 using software RAID. Command line used: iozone -s 190g -r 300k -O -b test_file OPS Mode. Output is in operations per second. ...
0
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1answer
77 views

Abnormal CPU usage during Disk Write Operations

I have a decent CentOS 6.5 dedicated host (CentOS 6.5/E3-1230 3.2Ghz Quad Core + HT/16GB/Software Raid 1 SATA II/WD2503ABYX/ext4) with the default CentOS kernel and "elevator=deadline" in grub. I/O ...
0
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3answers
53 views

Linux: Get information/stats about storage network

I want to know as much info as possible about the SAN a linux server is connected to. What commands will give me the most comprehensive view? Simply knowing the WWN of LUNS doesn't do much for me. ...
0
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2answers
12 views

Distributed LAMP vs DB and Web Server same box

We have a very read heavy semantic web (RDF) application which is RHEL 5/Apache 2.2.3/Tomcat 6/Java 6 on one Server, and MySQL 5.1 on another. Apache and MySQL are backported Red Hat repo stuff, so ...
3
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2answers
64 views

Intel Xeon E7-4807 vs Intel Xeon X5690

We replaced our main line of business server with a new one. The old server had dual Xeon X5690s in it (2 generation old chip), the new server has quad Xeon E7-4807s. We expect processor performance ...
1
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0answers
11 views

apache performance static file

I have a fairly low-budget VPS (1GB RAM + 2 CPU's) to run a few (5 - 10) different small websites (both static and dynamic). These websites have (very) low traffic (average of 500 unique visits for ...
0
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1answer
633 views

Performance Issue Between SQL and IIS on Seperate Machines

First time OP on serverfault, but an avid user of stackoverflow. We have two high-specification boxes, both running Windows Server 2008 R2 Standard. On one we have IIS 7.5, the other SQL Server 2008 ...
2
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1answer
2k views

what is acceptable datastore latency on VMware ESXi host?

Looking at our performance figures on our existing VMware ESXi 4.1 host at the Datastore/Real-time performance data Write Latency Avg 14 ms Max 41 ms Read Latency Avg 4.5 ms Max 12 ms People ...
12
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4answers
2k views

Why is 1 of my 24 CPUs Pegged at 100%?

I have an HP ProLiant DL380 G7 system using 2 6-core CPUs, with Hyper-threading enabled, for a total of 24 logical CPUs (as seen by Windows). When running our application, total system CPU ...
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2answers
34 views

Logging detailed network activity on Windows Server 2008

One of my clients is experiencing internet delays and outages within their small network. They've verified with their cable company that the issue is not related to any cable company outages. The ...
2
votes
2answers
96 views

Guaranteeing Shell Responsiveness on Pegged System

So my system is getting DOS'd, or I've just opened a kind-of-huge file (openstreetmaps planet.osm). The system goes totally unresponsive... so unresponsive that it'll take about 10 minutes to get into ...
2
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3answers
874 views

CPU/JVM/JBoss 7 slows down over time

I'm experiencing performance slow down on JBoss 7.1.1 Final. I wrote simple program that demostrates this behavior. I generate an array of 100,000 of random integers and run bubble sort on it. ...
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0answers
25 views

Optimizing disk performance on KVM VM configuration

I have a KVM host server running Ubuntu 12.04 LTS, bare bones installation with only KVM installed. The server has an 8 Core Intel(R) Xeon(R) CPU E3-1230 V2 @ 3.30GHz CPU with 32GB of RAM and SATA ...
3
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3answers
97 views

Can a Hyper-V machine be made slower and/or emulate a slow network connection?

I need to reproduce an issue with a client-server asynchronous communication (a bunch of JavaScript AJAX vs. an OData api), seemingly caused by some race condition in the calculations when the server ...
0
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1answer
724 views

openvpn TCP/UDP slow SSH/SMB performance

I have question about strange behavior of my openVPN configuration on Debian lenny. I have 2 server configs (one proto tcp-server based and one proto udp based). ISP bandwidth is 7Mbit/7Mbit. When I ...
1
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1answer
31 views

can Iowait cause significant RAM consumption increase

I have a node.js process running continuously on a linux EC2 instance, it extracts data and stores it in mysql. Some reads are also performed on the database. The process can run well during hours or ...
0
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0answers
27 views

when and how to appropriately use /proc/sys/vm/drop_caches

You can clear page cache with /proc/sys/vm/drop_caches. Can someone provide a practical explanation of how this works, when as a sysadmin you would want to do this, how to determine if your system ...
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0answers
6 views

Running Drupal on Amazon EC2 with optimal performance [duplicate]

I'm currently running multiple Drupal sites that have reasonably low traffic on an AWS EC2 m1.small instance. The EC2 instance is running Windows Server 2012 and IIS8. I'd like to know generally ...
71
votes
4answers
12k views

Why is TCP accept() performance so bad under Xen?

The rate at which my server can accept() new incoming TCP connections is really bad under Xen. The same test on bare metal hardware shows 3-5x speed ups. How come this is so bad under Xen? Can you ...
1
vote
1answer
44 views

MySQL high CPU usage on small website

I have a small website hosted on a dedicated server (FreeBSD 9.2, MySQL 5.6.1 and php 5.5.5). The problem is that MySQL eats a lot of cpu resources even if the website have a few visitors. The ...
2
votes
1answer
811 views

BackupExec 12 + RALUS - VERY slow backups

We use Backup Exec 12 and the Remote Agent for Linux/Unix Servers (RALUS) to backup a large RHEL5 system. For various reasons we need to do a daily working set job. These working-set jobs run ...
0
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0answers
44 views

Block requests based on hostname

Has anyone used this module in their Nginx setup? If yes, I would like to know about it's performance. How much would it affect the response time etc. https://github.com/flant/nginx-http-rdns The ...
1
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0answers
36 views

upgrade/reinstall vmware vsan from beta

Being a VSAN beta tester I decided to upgrade to GA version as VMWare suggests for production sites. They say, it is not possible/supported to upgrade from beta to GA version, and I did not upgrade, ...
0
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1answer
22 views

htcacheclean doesn't seem to be cleaning the cache

I'm running mod_cache with apache 2 on a fairly high traffic'd site. I've set the htcacheclean to run in demon mode every 10 minutes to keep the cache at 4GB. It's currently at 15GB and doesn't seem ...
0
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1answer
40 views

size of extent on LVM2

in LVM1 there was a limit of 65k extends. So size of extent had to been chosen carefully between wasted space on partitions (to big extent) and maximal possible size of logical volume (too small ...
2
votes
2answers
61 views

performance tuning vs understanding a memory leak?

I've read just about every blog post and serverfault answer relating to this, but have seen absolutely zero improvements to the server's CPU or Memory usage so I feel like I'm missing something. At ...
0
votes
1answer
58 views

Best way to optimize site speed for a large traffic website? [closed]

I'm currently managing a Website for a client of mine who gets about about 500-1000 visits minimum a day, and this includes Members uploading videos, photos, blog posts and other content. The site ...
1
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1answer
343 views

please explain my fio results - is O_SYNC|O_DIRECT misbehaving on linux?

I'm going mad over figuring out what the problem could be with one of our storage boxes. With a simple fio script I'm testing random writes using bs=1M and direct=1. The SSD is a Samsung 840pro ...
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0answers
10 views

mod_pagespeed own js and css render blocking

My mod_pagespeed gives a lower score because it's own js and css are render blocking. Given that the tool is designed to speed up, not slow down, I don't think this is desired behavior by design. Has ...
0
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2answers
62 views

How do I prevent a website on my server causing the whole server to crash

I have a server with 6GB of RAM and a 6-Core CPU. Number of websites hosted by the server is about 10, but sometimes 2 of them take 100% CPU and almost entire RAM which cause the whole server to crash ...
8
votes
2answers
9k views

Best Mysql cache settings for 8gb RAM dedicated mysql server using only Innodb (5gb database)

I'm a pretty big noob when it comes to setting up mysql for performance. And honestly I'm not worried about the fine tuning to squeeze every last bit of performance out of mysql, but I do know that ...
0
votes
1answer
813 views

Upgrading a PERC h310 to a PERC H710 mini RAID controller on a Dell R620

I have an ESXi 5.0 Free license host using an internal Datastore (RAID 5, 5 Disk) that was configured with a Dell PERC h310 RAID controller. The disk performance was very poor, so I upgraded to the ...
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0answers
34 views

Ubuntu server router - only 50% of upload bandwidth

I've changed my internet connection to 400 mbps download and 400 mbps upload. Real speeds when computer connected directly to optical modem: 421/412 mbps for download/upload. My network structure is: ...
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0answers
19 views

How do I check disk performance of LVM drive?

I have a CentOS server with 2 hard drives configured to use LVM over RAID1. How do I benchmark my hard drive? As seen in this question, I have used the following commands: # check read performance ...
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0answers
18 views

Frequent CPU spikes on fresh install

I just reinstalled my Server (Windows Server 2008 R2) and after installing MySQL 5.6, the CPU spikes every few seconds: http://s15.postimg.org/dno7ztfjf/cpuspikes.png Even worse than the higher CPU ...
1
vote
2answers
90 views

HP Smart Array P822 w. Dual D2700 - cabling for best performance

Reading the D2600/D2700 User guide, there's a section called "Cabling examples", but none of the examples match what we intend to do. I just want to make sure that it makes sense, before we do it. ...
3
votes
3answers
7k views

How to create a RAM Drive (RAM Disk) in Windows 2008 R2?

There are lots of tools for creating RAM drives. None of them seem to work for windows 2008 R2. Does anyone know if this is possible and if so how. Does anyone know of a tool that does work? I've ...
2
votes
4answers
2k views

apache poor performance with Kerberos Authentication

I have an apache instance that uses kerberos for SSO with an internal application that we have running. However the performance is very very poor. I believe from a tcp dump that when a user hits ...
1
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4answers
4k views

Bad disk performance on HP DL360 with Smart Array P400i RAID controller

I have a HP DL360 server with 4x 146GB SAS disks and a Smart Array P400i RAID controller with 256MB cache. The disks are in RAID 5 (3 disks + 1 hot spare). The server is running VMware ESX 3i. The ...
0
votes
1answer
781 views

How to understand random 500 internal errors in Nginx?

Our server is showing a lot of 500 internal error pages for random requests. We know the app is working because our code is unit tested. The server setup is Nginx with Unicorn running a single Rails ...
0
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0answers
18 views

Can the estimated time of access times for distributed keyvalue stores be below 1ms?

I'm digging through various Redis/Ceph/Elliptics benchmark to determine, whenever its theoretically possible to reach (very optimistic) request completion time below milliseconds in a non-SSD ...
0
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0answers
23 views

Debian mail server's Maildir folder with too many files causing disk I/O to go on high load

I have a Debian mail server running Postfix, Courier and Maildir, with disks on EXT3 filesystem. I have noticed that when I use my webmail application (Squirrelmail, in this case). It gets some kind ...
2
votes
1answer
92 views

My Ubuntu VPS is not using available swap, even if OOM. What to do?

I recently added 1 GB of swap to my Ubuntu virtual private server to prevent MySQL crashes on RAM overloading. I followed this tutorial. I use htop to monitor resources. When I use loadimpact to test ...
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0answers
21 views

IIS: how to determine most effective CPU throttling % [closed]

We have about 30-35 sites per server across 8-10 servers at a time depending on load, for a total of ~300 sites. The sites are more or less hosting slightly customized versions of the same .net web ...
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0answers
28 views

Poor XFS performance

I installed XFS but for some drives, it is giving me horrible performance issues, constantly at 100% utilization. I checked fragment, and more HDDs are fine (the ones at 100%): Device: rrqm/s ...
4
votes
2answers
181 views

VMXNET3 performance on Linux on ESX 5.0

What kind of performance can I expect from VMXNET3 adapter when running two Linux guests on the same VMware ESX private network defined between those guests? I use VMXNET3 adapter for communicating ...
5
votes
1answer
2k views

Apache on Win32: Slow Transfers of single, static files in HTTP, fast in HTTPS

I have a weird problem with Apache 2.2.15 on Windows 2000 Server SP4. Basically, I am trying to serve larger static files, images, videos etc. The download seems to be capped at around 550kB/s even ...