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

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0
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2answers
323 views

TCP - TAP performance

Linux. Is there a performance loss from using a tap device vs a hardware one like eth0 ? The goal is to create a user space tcp/ip stack and avoid the kernel as much as possible. I would like to be ...
1
vote
2answers
463 views

Performance Tuning Linux [closed]

Performance Tuning/ Monitoring/Latency keeping in mind I see following 4 items & in each item they are lot of tools. CPU Memory IO Network What I see following tools we do use. vmstat mpstat ...
0
votes
1answer
246 views

UFS wedge : “Out of journal space!” - how to tune? (FreeBSD)

I'm running FreeBSD 9.2p13 with UFS and journaled softupdates. Does anybody know how to tune softupdates journal on UFS? There are no suitable information in handbook, man pages or sysctl ...
2
votes
1answer
566 views

Azure IO performance sql server [duplicate]

We are in the process of migrating our on-premises sql server to Azure and I am having trouble with the IO performance. I have created a new D14 instance and attached 16 virtual disks at 100GB in ...
1
vote
1answer
934 views

Apache CentOS Server very slow! Wrong configuration?

I have a problem with server overload on a Apache configuration 8gb of RAM 1and1.com Virtual Server. Server gets extremely slow once it reaches 100+ active users (according to google analytics) during ...
0
votes
0answers
185 views

Packet loss between windows guest and Ubuntu 14.04 host

We are seeing packet loss between one of our Ubuntu 14.04 hosts and a KVM guest running Windows 2008 R2. The loss only shows up at high loads. Similarly loaded machines running 12.04 do not exhibit ...
1
vote
1answer
130 views

Read performance of old LTO-2 tape

I have a stack of old LTO-2 tapes, and my task is to save the contents as large binary files on disk for eventual consolidation on newer media. (The contents are in a custom format specific to this ...
0
votes
1answer
336 views

Improve openvpn bandwidth Debian 7

I configured openvpn on a dedicated server. Things are working fine but the bandwidth is not as high as it should be given the network specifications : The dedicated server has 250Mbps DL speed and ...
2
votes
2answers
261 views

How can I speed up PowerShell cmdlets that are using the -CimSession parameter?

As the title says, how could someone speed up the execution of this tiny script? Am I using the New-CimSession that right way anyway? $computers = Get-ADComputer -SearchBase ...
-1
votes
2answers
101 views

Parallel disk seek with JBOD

I'm looking to build a 80 TB file based storage system. Ideally, I'd like to do this with a large JBOD and one server with a lot of cores. My question is: Will JBOD containers (like Intel's) allow ...
16
votes
2answers
2k views

Is running permanently in a VMWare snapshot bad for performance?

I understand that the VMWare KB frowns upon long running snapshots mainly due to two things (In my opinion) Taking tons of snapshots can fill up the data store. Snapshots are simply delta files. ...
1
vote
1answer
309 views

Tuning Linux TCP for large number of TIME_WAIT

It looks like we have a bunch of tcp connections hanging around on a busy webserver, this is the output from ss -s: Total: 366 (kernel 1037) TCP: 72108 (estab 130, closed 71964, orphaned 0, synrecv ...
19
votes
2answers
4k views

How are CPU time and CPU usage the same?

In the Wikipedia page for CPU time, it says The CPU time is measured in clock ticks or seconds. Often, it is useful to measure CPU time as a percentage of the CPU's capacity, which is called ...
2
votes
1answer
74 views

Performance-wise, is a DNS Slave better to have than two duplicate Masters?

I have two bind9 servers that are not setup with duplicate settings and know nothing about each other. Our CPU usage is sitting around 7% - 10%: mostly bind, which I believe is perfectly in range for ...
0
votes
1answer
396 views

Why is Win Server 2012 slow to read data with RAID 5?

We have new HP 350p server with 4x 900GB 10k SAS disks with RAID 5 (win server 2012). But disks performance to read data is to slow - it's to slow to read big directory structure on disk. Where can be ...
1
vote
1answer
112 views

slow file server with contradictory values for CPU and CPL in atop

I've got a fileserver (centos 6.3) that slowed down suddenly earlier today. The cluster that mounts it could access other NFS mounts without a problem, but the access to this one was VERY slow. ...
2
votes
0answers
410 views

NGINX using 100% of the server CPU when testing with Blitz.io

I'm facing an issue here and after four days of looking around I decided to ask for some help here, after all a million heads can think a lot better than one. I have a Ubuntu 14.04 server setup with ...
1
vote
1answer
191 views

Strange Disk Benchmarking results for our storage, how to explain? [closed]

I recently tested the storage we got from our hosting provider. I don't know what raid config or how many disks the storage contains of. I used Atto Disk Benchmark which sends smaller and bigger ...
1
vote
0answers
27 views

Improve read performance on ext4 on Centos with software raid1? [duplicate]

I'm running a number of MongoDB nodes on dedicated servers running Centos6. Each machine has two SSDs which I have in Raid1 with two logical partitions: # df -h Filesystem Size Used Avail Use% ...
1
vote
2answers
119 views

What is the difference between truss -D and truss -E?

I am currently analyzing a command on Solaris that reads from a file and has very low performance. The truss -D commands shows me read system calls taking up to 0.03 seconds, but when I use truss -E, ...
1
vote
1answer
1k views

Ubuntu Server 14.04LTS Swappiness for server with 16GB memory

(don't worry I'm not asking what my setting should be, asking for the theory behind some conflicting advice I've read) My application is one that is lightweight and not under much load, but needs to ...
-2
votes
2answers
1k views

fastest way to transfer small files (faster than scp) [closed]

Scp is quite slow for transferring individual files. What is the quickest way to do this? The reason I need speed is not because I have a large number of files to transfer. I just want the individual ...
0
votes
1answer
410 views

What is the counter type for Linux's /sys/block/$DEVICE/stat

What are the counter types for /sys/block/$DEVICE/stat? $ cat /sys/block/sda/stat 8323741 42381356 464031898 19207478 1940738 49062039 408122282 79935459 0 22315734 99172579 Specifically, ...
1
vote
1answer
261 views

Website performance sluggish - High CPU and Disk Usage

Over the past couple of days my website's performance has been very sluggish, with queries taking a lot of time to execute. My CPU usage hit around 100% 4 times this week. Here is the output of top at ...
0
votes
1answer
391 views

PostgreSQL queries slower than before?

I am using PostgreSQL 9.3 server on my production server. Everything had been working fine for the past couple of months. But since the past week or so, PostgreSQL seems to have becomes very slow with ...
0
votes
1answer
100 views

Measure Dedicated Server Performance

I run an online video streaming site and keep getting more and more dedicated servers. Our business traffic fluctuates on an annual cycle which allows us to scale back our dedicated servers during the ...
0
votes
0answers
492 views

What happens on an SQL Server when a snapshot is taken by VMWare?

Recently I saw in our SQL Server logs that a snapshot could not be taken at the specific time and he retried it later on. During that timespan we had a huge performance problem. Besides the SQL Server ...
0
votes
1answer
2k views

How to solve performance problems with VMware ESXi 5.5 on old Dell PowerEdge 2900 hardware [closed]

I have a couple of old Dell PowerEdge 2900 servers that have come free and I would like to use them to host a mail server cluster. They are a bit old, but have been running workhorses for a while, ...
2
votes
0answers
1k views

Cannot set 1G speed on 10G nic using ethtool

I have a linux server with 10G fibre nics: xyz@xyz48:~$ sudo ethtool p1p1 Settings for p1p1: Supported ports: [ FIBRE ] Supported link modes: 10000baseT/Full Supported pause frame use: ...
0
votes
1answer
549 views

Is it safe and efficient to install HHVM on top Apache server with nginx as reversed proxy?

I've been trying to optimize my VPS for WordPress performance, and today, I decided to take it to a new level: I'm thinking about installing HHVM. Server status: My server runs Apache, and I have ...
4
votes
2answers
90 views

Multiple websites on multiple servers - seperate mysql or not

I currently have 2 Debian servers (VPS with 4 GB memory) and am hosting a variety of websites of differing importance: some are production sites, while others are demo/staging/test sites. ...
6
votes
2answers
276 views

Calling sync/fsync slows IO after 30 minutes uptime

After 30 minutes of uptime using Ubuntu 14.04 with an ext4 hybrid SSD I see many processes blocking IO using iotop. The root cause of this slowdown has been traced back to the Unix system call sync. ...
1
vote
3answers
3k views

Unexplicable extreme slowness on Dell PowerEdge R320, fixed only by cold reboot

At this customer's site, there are two new Dell PowerEdge R320 servers with the following configuration: A single 6-core CPU 16 GB of RAM 2x500 GB SATA disks in a RAID 1 array The O.S. is Windows ...
2
votes
2answers
909 views

Linux virtual memory tuning to workaround disk I/O issue

I am having a problem with a Linux server that it is writing to much to disk, thus I am having a slow response time due to a big IO wait. I already check smart values for the disks and are OK. This is ...
0
votes
2answers
3k views

Squid proxy performing extremely slow and sometimes doesn't work at all

I recently installed Squid on my desktop machine for testing purposes. I didn't edit the config whatsoever, and just pointed firefox at the proxy to see if it was working. Pages take an insanely long ...
-2
votes
1answer
107 views

Amazon G2 not giving a much better computing performance than my laptop CPU [closed]

I have a Java console application that performs Reed-Solomon error correction on large volumes of data (~700 MB at a time), just to test performance. The application is multithreaded, I can see it ...
0
votes
1answer
81 views

Negative effects of setting nginx workers too high

I've seen numerous posts advising how to set nginx's worker_processes, but very few detailing what happens when this is set too high. I'm about to run some benchmarks, but I'd appreciate advice on ...
-2
votes
1answer
45 views

How to check my site speed? [closed]

im the developer and in charge of a company's Wordpress based site our site started to run a lot slower recently and i am trying to figure it out for two weeks now! My main problem is that every ...
6
votes
2answers
227 views

Odd performance fluctation with php-fpm and nginx

I'm running a load test against a web service. It's a php application running on php-fpm and nginx, with fastcgi. There is a MySQL backend being used for small reads only. Invariably, I'm seeing a ...
-5
votes
1answer
268 views

Distance between DHCP server and remote pc effect performance? [closed]

Hey guys im doing a project where i have to create a WAN network however i was curious whether the distance of the DHCP server will bring down the performance loads if it was held from a different ...
1
vote
1answer
2k views

IPSec Site-to-site VPN speed between Germany and China very poor

we have successfully setup a Site-to-site IPSec VPN connection between our two offices in Germany and China. Below are the characteristics of both sites, VPN and current speeds: Germany VPN Router ...
1
vote
0answers
904 views

Why does chrome show a very long 'blocking' time (sometimes) when loading static files from Jetty 9

I'm seeing some strange behavior from Chrome when loading web resources from a Jetty 9.2.3 instance I'm setting up. In particular, I see some requests returning quickly, while others take a very long ...
0
votes
0answers
243 views

Azure disk performance

I am running on-demand, research D14 instance in Azure South Central US region, with a 4-disk RAID0. Recently the disk performance has become unusably slow, particularly the RAID performance, which is ...
1
vote
1answer
98 views

API and main page as two separated processes

SITUATION I created an REST API for my mobile application and now I want to create a website. API so far is very very simple, just for a couple requests like 'get list of contents', 'update some ...
2
votes
1answer
97 views

VMware VMFS5 Local Storage LUN Sizing

We have a VM ESXi 5.x host using local storage (DAS). It has 2 relatively large Logical Drives in RAID10 (10 HDD x1TB each). So, 2 LUNs of 5TB each. We are considering creating just two ...
4
votes
0answers
92 views

Windows Server 2003 terminal server extreme logon times

For the past week my users have been experiencing extreme logon times. They are generally in the 20 minute range or more. I will lay out my research below to see if anyone may know how to find the ...
0
votes
1answer
4k views

Performance issue HYPER-V : VM shows very high CPU use, but the Physical machine shows very small CPU use

My Hyper-V VM(Server2008R2, SP1) shows very high (almost 100%) CPU use when fully under heavy load (6cores from total physical 8cores, 25Gb RAM from total 32GB) - used as TS, Picture TOP right corner ...
1
vote
1answer
599 views

MongoDB high CPU usage

Running MongoDB 2.4.11 on Ubuntu 14.04.1 LTS In top, this mongod thread is constantly using ~195% CPU: PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 24524 mongodb 20 ...
0
votes
1answer
223 views

Website slowing down when many users access simultaneously [closed]

I'm new to web development. I have hosted my website through a free web hosting service providing free subdomain. The free hosting service says that they provide 100 GB bandwidth. I just upload files ...
0
votes
2answers
168 views

Are there any performace gains to using Varnish along php-fpm and nginx? [closed]

PHP-FPM 5.6 and Nginx 1.6.2 would no doubt give maximum performance, at-least speed wise. So, I would like to know if there are any pros/cons to adding varnish cache to gain probably few more speed. I ...