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Questions tagged [performance-tuning]

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

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Apache Tuning for 512GB RAM

Use Case: API Server Cluster Optimized for JSON Data Submission I have a distributed application sending info to API servers that are slaves of a MySQL 8 master. Applications do full initial sync (~...
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1answer
984 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
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How do I tell how close I'm getting to somaxconn?

The sysctl option net.core.somaxconn defaults to 128 (on our systems) but can be raised. What exactly is this limit measuring and capping? How do I find out how close I am to the limit? Context: I ...
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Online performance tuning apache tomcat

I'm relatively new to this field and not sure whether I'm posting the question in the correct forum. I'm trying to do online parameter tuning for the TPC-W benchmark. (It is a 3-tier web application ...
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How to ask antivirus software to work slower and hence use less disk access?

It is our policy for our end-user's computers (usually laptops) to have high power CPUs, GPUs, RAMs (no less than 16GB) and HDD space (1TB), but we save money by choosing lower rotation speed of HDD. ...
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What does sunit=0 and swidth=0 mean for XFS file system?

I created an XFS file system using default parameters at the time of creation of a system. Now looking at the output of xfs_info, it show 0 for the values of sunit and swidth. I can't seem to find ...
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1answer
1k views

Preventing PHP-FPM from crashing under light load

I'm getting a DoS attack on a wordpress site that I host. 173.192.109.118 - - [30/Sep/2015:22:31:36 +0000] "POST /xmlrpc.php HTTP/1.0" 499 0 "-" "Mozilla/4.0 (compatible: MSIE 7.0; Windows NT 6.0)" ...
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Why am I getting a Sudden Drop in throughput and sluggishness with no CPU increase

Occasionally, during random parts of the day, I get a 10 minute period of extreme sluggishness where my requests are taking 50-1000 times longer then they normally do. Note: I am on Apache/2.2.16 (...
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4answers
452 views

Options for performance improvements on very big Filesystems and high IOWAIT

I have a Ubuntu 16.04 Backup Server with 8x10TB HDD via a SATA 3.0 Backplane. The 8 Harddisks are assembled to a RAID6, an EXT4 Filesystem is in use. This Filesystem stores a huge amount of small ...
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1answer
1k 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
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Debugging and fine-tuning the linux process scheduler

When debugging sporadic web application slowdowns, I've found that all the processes have quite high maximum scheduling delay. # perf sched record -- sleep 10 && perf sched latency --sort max ...
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Is it possible for Windows clients to carry out external queries through an alternative DNS server directly?

Our Windows domain is far away. DNS performance is affected. Would it be possible for Windows clients to carry out external queries through an alternative DNS server directly? I understand this is not ...
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2answers
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Dual-port RDMA Throughput Issue

I have two nodes connected with dual-port Mellanox Connext-X3 VPI HCAs via an IB switch. The nodes are two socket machines with Hasswell CPUs and 2 16GB DIMMs per each socket (totaling 64GB). ...
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How increase write speed of raid1 mdadm?

CentOS, Xeon 1230, 16 Gb RAM, 2x1TB SSD in raid1 (mdadm). Read from raid1 vary from 130 to 250 MB/s depends of files etc. But write speed very slow: 15-20 MB/s (iotop, mc etc.)! You know the real ...
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1answer
2k views

Tuning Apache KeepAlive Timeout for HTTPS

My website forces HTTPS everywhere and has an average first load time of 3-5 seconds. Thanks to caching, repeat load time is 0.8 seconds. The SSL negotiation takes 150-300ms on my server, so I want ...
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1answer
2k 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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1answer
315 views

Nginx: Optimizing server response time for a HTTP cached website

I have a website with all of the pages served from nginx’s http cache and rarely invalidated or expired. The average total page download size is around 2 MB But despite being a static site with no ...
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1answer
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Nginx performance issues with single user reqesting but with large configuration file

I have following configuration used in server block and as the number of locations grew, the performance has degraded substantially even if there is only one request (e.g. https://example.com/loc1/...
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1answer
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what is the IOPS behavior when partitions of single disk are used in an LVM?

I have an ubuntu 14.04.1 LTS server which have LVM(backed by hardware RAID5) with logical volume and a volume group named "dbstore-lv" and "dbstore-vg" which have sdb1 sdb2 sdb3 created from same sdb ...
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1answer
212 views

How to find out the response time for C-state to change to higher mode

How much time does the CPU wait to go to higher mode, let's say from C0 to C1? Or if it can be customized, where can I find the current value? Also, does the the C-State changes in stages like first ...
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1answer
2k views

Copying cause big iowait

I have dedicated server with 3 HDD. System disk, backup disk (same as system disk) and data disk. When I copy lot of data with cp (say, between backup disk and data disk) load average goes sky high. ...
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I/O performance issues with dd “benchmark” on XenServer 7.1 using SLES12-SP3 in HVPVM mode

Why does SLES12-SP3 in HVPVM mode perform that badly compared to the other two? SLES12-SP3 VM inside ESXi 5.5: Device: rrqm/s wrqm/s r/s w/s rMB/s wMB/s avgrq-sz avgqu-sz ...
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1answer
1k views

Will noatime on a tmpfs volume improve performance?

I am using /run/shm/myfolder for nginx micro caching, also keeping ngx_pagespeed files there. I am wondering if there will be a speed increase if I go from relatime to noatime? It's for HDD, but on a ...
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1answer
391 views

php memory_limit vs kubernetes resource memory limit

I'm new to Kubernetes and I'm trying to figure out what resource limits I should set for my php webapp. My first guess is that if I have configured php fpm to use a maximum of 256M of memory then ...
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Performance on Pinned CPU cores versus automatically managed?

I have a XenServer 7.5 environment where I'm running a single Windows VM with 16 total vCPU's. My server has dual Xeon E5-2620v4 CPU's with 8cores/16threads each clocked at 2.1GHz nominal and a Max ...
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1answer
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How do I tune a single-threaded server to be amazingly fast? [closed]

We have a license manager server that runs on a single host. It accepts TCP connections, performs some sort of exchange (I haven’t reverse-engineered it), and keeps the TCP connection open for the ...
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How to tune the performance of a Nginx webserver in ubuntu16.04 [duplicate]

My server is ubuntu 16.04 and 8 core machine with 16gb RAM. I need to get the best performance with this configuration. How can I tune the server with Nginx level and system level? Running a PHP LMS ...
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2answers
10k views

Does 'tuned' need to keep running?

On my CentOS 7 systems, I use tuned-adm to set a profile appropriate to the environment during configuration, but after that, I never subsequently change that profile. It seems that the tuned system ...
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2answers
4k views

Mysql innodb_buffer_pool_size in relation to innodb_buffer_pool_instances

I run a virtual server with an Owncloud installation on it. Now Owncloud has the problem that the way it's developed at the moment, each file upload causes a little MySql overhead. So is very ...
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3answers
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CPU0 is swamped with eth1 interrupts

I've got an Ubuntu VM, running inside Ubuntu-based Xen XCP. It hosts a custom FCGI-based HTTP service, behind nginx. Under load from ab the first CPU core is saturated, and the rest is under-loaded. ...
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Website performance issue while servering a request

we have build a website to provide search in some specific area. For that we have used apache Solr (6.x), HAPROXY (1.6) and apache web server on a single system with CentOS as OS. our expected users ...
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2answers
24k 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. Configuration CPUs: 2 ...
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Ubuntu Server Performance Issues with CockroachDB

I have a cockroachdb node I am playing with. My box has Ubuntu 16.4, 64 GB of RAM, 4 physical cores (Quad Core Intel Xeon 3.3 GHZ). Inserts to this DB are very slow. On a 100000 sample set, average ...
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1answer
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Analyzing server performance [duplicate]

We have recently finished work on one ecommerce site which is built on opencart 2.x and site has around 1k products. The site is currently running on VPS server. For some days we are facing some ...
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1answer
393 views

Recommended Apache tuning configuration [duplicate]

My web server has configuration 16 GB RAM 8vCPU (Hexcore). Apache version 2.4. There will be massive site visit. So what will be the best and recommended Apache tuning configuration ? I am using ...
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9answers
56k views

Apache Tomcat chokes after 300 connections

We have an apache webserver in front of Tomcat hosted on EC2, instance type is extra large with 34GB memory. Our application deals with lot of external webservices and we have a very lousy external ...
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1answer
246 views

Slow apache response time for json api (solved)

I've got an Apache server hosting several json APIs. This server is running Ubuntu 16.04.4 LTS with Apache and Mysql. Response times for all API are very good except for one! It takes about 5s to ...
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6answers
8k views

Configuring NTFS file system for performance

We have an application that is planning to store around 1.1TB of XML files which average 8.5kb in size. These represent a rolling 18 months of data, with around 200,000 new files being created every ...
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2answers
4k views

Why is my bare-metal 16x 2.93GHz cores computer performing poorer than a VPS with 4x 2.5GHz cores?

I have a written a piece of multi-threaded software that does a bunch of simulations a day. This is a very CPU-intensive task, and I have been running this program on cloud services, usually on ...
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2answers
2k views

BTRFS, sector alignment and Advance Format Disks

I want to set up a BTRFS RAID1 setup with two WD Red 4TB disks, which possess 4K sectors. Since I am keen to get it right the first time before copying data to it (yes it will be backed up), my ...
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1answer
213 views

Persist statistics data from Postgres' stats_temp_directory on demand

We are investigating I/O load in one of our VMs and possibilities to optimize it and it showed that most of the load is generated by the stats collector of PostgreSQL. It jumps between 3,5 and 6,5 MB/...
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5answers
41k views

Find out which task is generating a lot of context switches on linux

According to vmstat, my Linux server (2xCore2 Duo 2.5 GHz) is constantly doing around 20k context switches per second. # vmstat 3 procs -----------memory---------- ---swap-- -----io---- -system-- --...
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1answer
630 views

Apache handshaking slow on prefork configuration, need config tuning

My server, running Ubuntu 14/Apache2.4.7, has an htaccess redirect to force all requests to use HTTPS. Generally, it responds quickly. However, I recently altered my SSL config to restrict the ciphers ...
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2answers
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Hyper-V Windows Server 2016 VM is super slow

I have a Hyper-V VM, both host and VM are running Windows Server 2016. The VM has Exchange 2016 installed and takes an hour to start up fully (all Exchange services). It is actually very solid when up ...
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7answers
16k views

Is it OK to run perfmon on production servers? And why?

Or should perfmon be limited to a Dev/QA server with load tests that simulate production activity? I'd like to run perfmon for two days (like Sql Server master Brent Ozar suggests) to get an overall ...
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2answers
299 views

DRBD weird speed dips

couple of weeks ago I made a test setup for DRBD on couple of servers. The speed was fixed 90MB/800Mb as per my config for initial sync. Now I have reinstalled the OS (CentOS 7.4) to do final install ...
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1answer
1k views

nfs server getting many rpc-srv/tcp: nfsd: sent only 700260 when sending 1048708 bytes - shutting down socket

System is running CentOS 7.3, serving files over both ethernet and infiniband, but the vast majority of traffic is over infiniband I just stood up a new file server that is now generating large ...
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1answer
223 views

Misunderstanding about Page Cache and dirty_background_bytes

I've been looking at this for a while now and things aren't lining up with my expectations, but I don't know if it's because something is off, or if my expectations are wrong. So, I've got a system ...
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3answers
2k views

How to turn linux to keep 'cache' high?

We are running a heavy service on Debian. Our service generates lots of file i/o and its performance relies on how well Linux kernel caches files. Our system has 64GB memory. Total file size is 500GB ...
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1k views

best configuration for 5k requests per second apache [duplicate]

I have a webserver which has 5k requests per second this overloads my server with the cpu usage host has 12 CPU and 8GB ram [ almost not in use ] my httpd-mpm configuration is below : <IfModule ...