Performance tuning is the process of modifying a system to improve its efficiency. This is also known as optimizing.

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Changing memory allocator to Jemalloc Centos 6

After reading this blog post about the impact of memory allocators like jemalloc on highly threaded applications, I wanted to test things on a larger scale on some of our cluster of servers. We run ...
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1answer
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difference between taskset and cpuset

I'm trying to reduce the latency of my linux network application. I've learned that there are two tools for "binding" a program to particular CPU core: taskset and cpuset. Which one should I prefer? ...
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TOP processes by system time

I have a system running 2 processes - MySQL and Java I'm seeing 20-30% of the time spent in %system. I've looked around to try and find a way to identify which what the balance of the system time is ...
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Solr Query thread limit

While performing stress tests of our website, it looks like Solr could be bottleneck. It has enough ram, CPU usage is far from 100%, but we still facing problems of waiting for solr response for even ...
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2answers
283 views

Low latency TCP settings on Ubuntu

There is a server for measurements running on Ubuntu in my lab . And there is C program, which receives data through TCP connection and should as soon as possible send a reply. Network latency when ...
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Tunning nginx/php5-fpm : why low memory usage with 800 users?

I did optimize nginx with what I found on the internet My specs are 2 servers load balanced : Intel Xeon E5-1620v2 (4c/8t 3,7 GHz+/3,9 GHz+) 32 Go DDR3 ECC 1600MHz 3x 160Go SSD Intel DC S3500 SATA3 ...
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78 views

Optimize Apache for EC2 micro instance

I'm running apache2 on a EC2 micro instance with ~600 mb RAM. The instance was running for almost a year without problems, but in the last weeks it just keeps crashing, because the server reached ...
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2answers
54 views

Centos Server Recently slowed down significantly

I have Dedicated Server on 1and1 with RAM - 16 GB HD 1000GB CPU: Intel(R) Xeon(R) CPU E3-1270 v3 @ 3.50GHz, 4 cores Centos 6 Apache/2.2.15 PHP 5.3.3 Mysql I have a video sharing website (on ...
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59 views

MySQL performance problems on particular vhosts

I have a dedicated server setup (8 cores, 16 GB of RAM), running Ubuntu 12.04 LTS with latest updates, and I am experiencing some performance problems related to MySQL. I have multiple vhosts active. ...
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29 views

How to alleviate high disk reads on server?

We are currently hosting a 3TB library of image galleries on our web server, all searchable by users. With about 400 active users at a certain time on the website, our disk reads are pushing 100% I/O ...
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1answer
942 views

apache and ajp performance

I have an apache sitting in front of two tomcat app servers(one on the same physical server, the other on a different one) that does time consuming work(0.5 sec to 10sec per request). The apache http ...
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1answer
2k views

Lot of FIN_WAIT2, CLOSE_WAIT , LAST_ACK and TIME_WAIT in Haproxy

We are running haproxy in production for around 10k+ concurrent users. But we are seeing lot of FIN_WAIT2, CLOSE_WAIT , LAST_ACK and TIME_WAIT in the netstat output. This output is on a 8G ...
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10 views

Apache Performance Tuning - StartServers and SpareServers [duplicate]

I administer a cluster of EC2 c3.xlarge instances which sit behind an Amazon ELB and run Apache to serve a PHP web app. The current Apache prefork configuration was ripped from our old managed ...
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44 views

Nginx+Tornado performance tuning?

I have written a Tornado based Server that makes readouts from files on disk available via http. The size of the readouts I am serving is either about 10kb or about 1MB. I have a server machine with ...
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1answer
659 views

How to remove the pause during JBoss 5.1.0 GA boot between ProfileServiceBootstrap and AnnotationCreator?

I've managed to strip down my JBoss profile enough that it boots in 1.5 minutes. I started with the web profile and started pulling out stuff I didn't need. The bulk of my boot time can be seen here: ...
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1answer
34 views

What is the correct way to track and monitor Exchange DB replication “pressure” over time?

I want to determine if some databases are overloaded or unbalanced, and think that looking at the transaction logs created per database over time would tell me which DB is at risk of missing RPO ...
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25 views

Multipath tcp application level performance measurement

I am working on a project related to Multipath tcp and I want to measure the goodput and the RTT at the application level. I don't want to use a traditional tool(netperf, iperf, ...) and I want to ...
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5answers
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Windows Server 2008 R2 poor CPU performance

We have two identical servers with the following specs: 4 sockets containing AMD Opteron 6172 at 2.10 GHz each of which have 12 cores 64 GB RAM One runs Windows Server 2008 R2 Standard, which ...
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2answers
321 views

Linux : SSD performance tweaking queue

I've allready applied well known mountpoint options for ssd, enabled stuff in LVM for ssd optimisation as well. Now i've ran into a possible challenge. Would it be possible to gather information on ...
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1answer
50 views

Execute ps1 script when CPU threshold is meet

I'm looking for a function similar to Debug Diagnostics Collector. Where you can setup a performance (or any counter) trigger (eg. above 50% CPU over 50 seconds). Once condition of a trigger are ...
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1answer
93 views

4096 and 8192 block size read slower than write? by using lsi 9361-8i RAID10

is it possible that 1024 and 2048 block size read speed is faster than 4096 and 8192 block? I'm using lsi 9361-8i with RAID 10 , with 8 x Kingston E50 250G. result: 1024 = Write: 2,251 MB/s ...
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58 views

The `iostat` Command Describes a Non-Existent Block Device

The System An instance running on Amazon EC2 It is an m1.large EC2 instance The instance is running Ubuntu Server 12.04 LTS Here's What Happens... I wanted to measure disk IOPS on my system, and ...
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2answers
370 views

NFS Over OpenVPN: Top Performance Boosters

I have two VPS's - One is running 2008 Server R2 and the other is a Ubuntu 12.04 installation. I am using the Windows VPS for RD sessions for Quickbooks and a couple other apps and using the Ubuntu ...
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46 views

IRQ not handled by all CPUs

I have a problem about balancing irq. I took irq numbers from /etc/interrupts and assigned each irq to each of 24 CPUs as this tutorial says for i in {143..166};do cat /proc/irq/${i}/smp_affinity; ...
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1answer
128 views

performance monitor in iis 7 to monitor which website is using most resources (asp.net)

I am using Windows Server 2008 R2 and IIS 7.5, and am hosting multiple websites on the same webserver. Is it possible to use Performance Monitor to know on average which website is using the most ...
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99 views

Lots of packets pruned from receive queue because of socket buffer overrun - reason to worry?

I know this question has been asked before, but maybe not in this particular context: I have a setup with a couple of MS2008R2 HyperVisor servers running a number of Ubuntu guests. Our webproxy runs ...
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85 views

famd/gamin timeout issue with courier-imap

I'm running a mail server for about 200 users with courier-imap on Debian 7. This server is running a linux kernel 2.6.38 inside a Xen guest having 2 cpu cores and 2 GB RAM. The server accept ...
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1answer
56 views

how to disable all caches types in mysql server in order to do performance testing for my queries

I'm using Mysql Server 5.6.15 and i have a huge database with many complex queries. it seems that when I run the query the first time it takes X amount of time. when I execute it again it takes ...
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93 views

What's the bottle neck of server hit 100K request?

The following are two graph of my digital ocean vps instance handle load test request. 10K/s, The only different is the request file size, first is 10K, the second is 20K. Can any one point out the ...
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1answer
117 views

PHP Settings [pm.max_children, pm.start_servers, pm.min_spare_servers and pm.max_spare_servers]

In the midst of transferring a website from a GoDaddy shared server to an EC2 instance. Handling the traffic, which during peak times on a typical day is around 300 active visitors, has been ...
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1answer
51 views

Server load avg. hitting 16-20, but all resources under 90% usage?

As you can see in the image shared below, the server load peaked to almost 20 but the CPU, RAM, DISK IO and Network I/O remained well under their full capacity. My question is: 1). What caused the ...
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2k views

How do I increase UDP Recv-Q

I have a gigabit connection that is not fully utilized but I am getting packet receiving loss. When I do netstat, it shows the Recv-Q sometimes maxes out at 262656 during heavy traffic. Proto Recv-Q ...
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77 views

tuning apache for low ram low traffic server

I have a low end VPS server with 512megs of ram to host downloads of files (~10-25megs each). what is a good configuration for the following parameters in apache. I expect no more than 10 human users ...
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4answers
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FreeBSD performance tuning. Sysctls, loader.conf, kernel

I wanted to share knowledge of tuning FreeBSD via sysctl.conf / loader.conf / KENCONF / etc. It was initially based on Igor Sysoev's (author of nginx) presentation about FreeBSD tuning up to ...
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1answer
252 views

rmem_max more than rmem_default

I just installed centos 6.3 freshly and noticed the following: [root@localhost user1]# cat /etc/redhat-release CentOS release 6.3 (Final) [root@localhost user1]# [root@localhost user1]# cat ...
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OpenSSL performance oddity

I've seen something odd regarding OpenSSL performance. This is the output of 'openssl speed aes-128-cbc' on a physical HP Bl460c Gen8 with dual E5-2680's running RHEL/OEL 6.4x64 and OpenSSL ...
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Ubuntu backup script kills performance

I run a nightly backup, which takes about 1 hour. During that the performance is bad as hell. It looks pretty much like this: # DB dump ionice -c 3 nice -n 20 mysqldump --skip-lock-tables --user=foo ...
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yslow says etags are misconfigured. how to configure etags properly on IIS7?

running ySlow on a website I support, I noticed it reported that the etags are misconfigured for the site images (e.g. *.jpg, *.png, *.gif). Can anyone help explain what I have to do to get IIS7 ...
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4answers
15k views

How to achieve 500K requests per second on my webserver? [closed]

I recently gifted myself a new dedicated server and I am trying to squeeze maximum performance out of it, for fun and learning. I am trying to achieve maximum possible requests per second this server ...
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35 views

SQL Server : Improve SIMPLE SELECT to retun 2 LAC Rows faster?

We have a stored procedure in which we are creating a temp table which has more than 200,000 rows with 30 columns (2 of DATETIME, 4 of INT, 5 of [numeric](20, 3) and rest of VARCHAR(500) data types. ...
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4answers
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How to check for bottlenecks in Windows Server 2008 R2

I recently switched out a 10 year old server for a brand new server in a small office and upgraded from Windows Server 2000 to Windows Server 2008 R2. After the switch was complete and some ...
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1answer
248 views

How to identify which MySQL queries take a lot of time?

My MySQL server is consuming a lot of memory. Memory footprint 1. Memory consumption in descending order (top 4) MySQL's memory consumption in particular - Why is there so many number of mysqld ...
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1answer
184 views

KVM Slow performance on XP Guest

The system is very slow to do anything, even browse a local folder, and CPU sits at 100% frequently. Guest is XP 32 bit. Host is Scientific Linux 6.2, Libvirt 0.10, Guest XP OS shows ACPI ...
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1answer
4k views

Improving OpenVPN Performance

I've been trying to improve my OpenVPN performance and this is my current setup: cat /etc/openvpn/server.conf port 443 #- port proto tcp #- protocol dev tun #tun-mtu 1500 tun-mtu-extra 32 #mssfix ...
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1answer
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Manage Win7 Performance Options via GPO

Our company has many virtual Windows 7 instances. Based on recommendations from VMWare, we want to customize the visual effects to optimize performance. We have found that we can change the following ...
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How to exclude requests from unwanted sources

Scenario: Client buys our analytics services and includes our analytics SDK in his mobile app. Users who download the app will start sending us lots of data. When the client stops paying for our ...
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what does locked % in mongostat mean?

When running mongostat to look at our mongo database, I'll frequently see the locked % number jump up, sometimes as high as 80%. Here's a few example rows: insert query update delete getmore ...
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811 views

MySQL Memory usage

Our MySQL server seems to be using a lot of memory. I've tried looking for slow queries and queries with no index and have halved the peak CPU usage and Apache memory usage but the MySQL memory stays ...
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How to improve server performace? [closed]

Scenario After an integration of our product with a site that have a "decent" number of request, development team of that site ask me to prove that our server can handle traffic generated from that ...
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2answers
119 views

ZFS Equivalent of lvdisplay snap_percent

I've been using LVM snapshots for backing up MySQL databases. FLUSH TABLES WITH READ LOCK is issued and then lvcreate --snapshot --size 4G etc. Because the database is live while the snapshot is ...