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

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2
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3answers
1k views

Linux vs OpenBSD vmware performance

I wonder what experience others have of running openbsd on top of vmware infrastructure. I have a pretty regular Lighttpd+Mysql+PHP5 setup of 2 vmware guests: -Debian7 Wheezy -OpenBSD 5.2 (this ...
3
votes
2answers
545 views

Questions about storage performance

I would be glad guys, if you can answer me some of my questions about the performance of our storage. The setup HP P2000 SAS with 2GB cache 8x 1TB SATA 7200 RPM storage RAID6 3x hosts with SAS HBA ...
1
vote
0answers
36 views

File IO being slow

I've rented this root server with a RAID1 mdadm software raid setup. Using dd to benchmark the file IO speed it achieves 230MB/s write (default blocksize). Certain tasks such as mysql are way slower, ...
18
votes
3answers
9k views

OpenVPN performance: how many concurrent clients are possible?

I am evaluating a system for a client where many OpenVPN clients connect to a OpenVPN server. "Many" means 50000 - 1000000. Why do I do that? The clients are distributed embedded systems, each ...
4
votes
1answer
1k views

Does increasing the journal size improve performance for ext4 filesystems?

There is an article on linux-mag which says that increasing the size of the journal on ext4 filesystems actually improves filesystem performance for very large partitions. I'm wondering if anyone ...
1
vote
1answer
109 views

What can explain Hyperthreading bringing a server to its knees

In the last year I've had 2 brand new servers that I commissioned where their performance made them unusable. The both servers were Dell R620 servers with 1 processor. One had 6 cores and the other ...
10
votes
10answers
976 views

How does the number of subdirectories impact drive read / write performance on Linux?

I've got an EXT3 formatted drive on a Linux CentOS server. This is a web app data drive and contains a directory for every user account ( there are 25,000 users ). Each folder contains files that ...
7
votes
4answers
9k views

How can I find out what is causing interrupts on Windows?

Occasionally I come across servers (Windows 2003 and 2008) with high processor % interrupt time. Is there a way to see what program or device is causing the interrupts?
3
votes
1answer
1k views

How to achieve multiple NFS/TCP connections to the same server?

I'm trying to maximize the NFS/TCP bandwidth between a Linux client and a single NFS server over a 10Gbps link. Although each NFS mount has its own device (major/minor), everything comes down to a ...
0
votes
1answer
113 views

Dynamics CRM 2013 on premise workflow performance

We are speaking of the time it takes for the workflow state machine to notice that task A is complete, thus satisfying a wait condition in a workflow definition, which then creates task B. User1 ...
2
votes
3answers
2k views

High disk I/O activity in CentOS server

I have about 16 websites in a CentOS dedicated, and I am having some problems on high traffic hours, it seems to be a high disk I/O activity causing a general slowdown. I've installed atop and this ...
0
votes
1answer
74 views

Is it better to store the MySQL database directory on a separate RAID 1 device?

We have a Linux server with a RAID 1 using two HDDs on which runs a Apache server managing multiple sites and some other services that interact intensively with the databases and produce massive ...
2
votes
2answers
45 views

Postfix long dns queries

I use my postfix server as a relay to another provider. I dig a little to find out why sending a simple mail takes so much time. I figure out that postfix do complete DNS queries for each single mail ...
-3
votes
1answer
112 views

Mysql showing 100% CPU usage [closed]

I'm experiencing some problems with my MYSQL server installed with Cpanel. My server is showing 100% usage of mysql even if I don't have too much traffic on web. I am running CentOS 6.5x64 with 80GB ...
3
votes
1answer
1k views

CentOS Tuned Equivalent For Debian

Running a few systems, a few are Debian which have been great. I have on the CentOS boxes tuned(tuned-adm) installed and setup for throughput. I searched all over Google and only found some articles ...
-1
votes
1answer
1k views

High CPU Usage in windows server 2003

In one of our production servers the CPU usage is 100% and thus some of the backup jobs failed. In windows server 2003 cms.exe shows : 50%, tomcat_3.exe : 25%, and tomcat_1.exe : 25%. Please help me ...
0
votes
2answers
33 views

Same number of clients - multiple WAPs vs Single WAP

We purchased a device that acts as a WAP through which you can connect a mobile device and share its content onto a projector or tv. My question is - if we have multiple deployments of this device, ...
3
votes
4answers
198 views

What is a core, and will purchasing more cores for my VPS speed up page load times?

I recently purchased a premium WordPres plugin called Hide my WP. I planned on using this plugin for my nonprofit organization's website, which is a multisite WordPress installation with an SSL. ...
1
vote
1answer
25 views

server connection speeds can the be judged by a online speed test [closed]

Im currently investigating some issues on my windows servers. Ive run a test from my hosting provider and I think its incredibly slow. I've also run the same test but from my amazon AWS box and ...
3
votes
2answers
3k views

Slow disk performance on Azure Virtual Machine

Okay, so first of all, allow me to say that I'm not an operations person, but a developer. So I'm going into a bit of unknown land here, so please bear with me. I would like to use a Azure Virtual ...
13
votes
11answers
15k views

How to monitor and log the memory/cpu usage of processes over time? [closed]

I am looking for a way to diagnose issues, such as swap death, where a balooning memory process fills up swap and kills the whole machine (such as apache). I'm already using cacti and I can set up ...
18
votes
4answers
1k views

Software vs hardware RAID performance and cache usage

I've been reading a lot on RAID controllers/setups and one thing that comes up a lot is how hardware controllers without cache offer the same performance as software RAID. Is this really the case? I ...
0
votes
2answers
2k views

Measure & benchmark the speed & latency of file access on a mounted NFS share

I have a Linux Centos system that mounts some NFS shares, what technique can I use to measure the I/O speed/latency/rate when reading and writing files from that share? Could this technique also be ...
1
vote
0answers
32 views

How do I interpret a very high Avg. Disk sec/Write perfmon value?

Short version: Is the perfmon screenshot shown below enough evidence to say "something is wrong with your storage system"? Long version: I am debugging a performance problem: Some SQL Server query ...
4
votes
2answers
216 views

Samsung 850 EVO + HP P410 limited iops?

I´m experiencing a weird write iops limitation with a HP P410 256mb cache controller and 4x consumer grade ssd´s (Samsung EVO 850) in RAID5/10. After upgrade to latest firmware (6.64) for HP P410 ...
0
votes
2answers
24 views

MyISAM Throughput spike at 12000 record insert

I am testing database performance with bulk record inserts. Both systems are identical apart from storage engine **Database 1000 4000 12000** MySQL_InnoDB 60.95330976 ...
1
vote
0answers
45 views

mysql dump import incredibly slow on my developer's machine [migrated]

I have an SQL dump, it's pretty big (411 MB) and it took 10 minutes to import on server A, the same import on my workstation B has an estimate (pipeviewer) of 8 hours to import (it imported 31 MB in ...
7
votes
1answer
10k views

How to troubleshoot latency between 2 linux hosts

The latency between 2 linux hosts is about .23ms. They are connected by one switch. Ping & Wireshark confirm the latency number. But, i dont have any visibility into what is causing this latency. ...
4
votes
2answers
623 views

Why iperf still reports 1Gbps performance when using bonding over two 1Gbps adapters?

As I understand it, bonding brings among other benefits the ability to increase the network speed between two machines in a LAN. Bonding [...] means combining several network interfaces (NICs) to ...
15
votes
2answers
279 views

NFS poor write performance

I have two machines connected with 10Gbit Ethernet. Let one of them be NFS server and another will be NFs client. Testing network speed over TCP with iperf shows ~9.8 Gbit/s throughput in both ...
17
votes
5answers
51k views

High load average, low CPU usage - why?

We're seeing huge performance problems on a web application and we're trying to find the bottleneck. I am not a sysadmin so there is some stuff I don't quite get. Some basic investigation shows the ...
2
votes
1answer
21 views

Same hardware/software, significant difference in performance

Introduction I have two sets of machines, set A and set B, with apparently the same hardware/software configuration, but with a significant difference in performance. Machines in set B are up to x4 ...
19
votes
5answers
1k views

Extremely fast booting server

I'm changing the way that our DHCP/DNS stuff works at work. Currently we've got 3 DNS servers, and a DHCP box. All of them are VMs. There's a circular dependency where stuff booting requires NFS, ...
7
votes
1answer
130 views

What do users see when Apache reaches MaxClients?

Occasionally, in my Apache error log, I will find: [error] server reached MaxClients setting, consider raising the MaxClients setting I've purposely lowered MaxClients in the past (to 60) due to ...
0
votes
1answer
668 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 ...
0
votes
1answer
34 views

Does Apache mod_status give any insight to tuning Apache config?

Does the Apache mod_status output give any insight to tuning Apache prefork config? For example, using Apache's mod_status, I figured out that My server gets 3 requests/sec average, the range is ...
1
vote
0answers
24 views

Run application from network drive takes long

This problem started recently, and I wasn't able to find a solution. Not even formatting solved. We have a program on our network drive and the Whole company accesses to this single exe. Usually the ...
20
votes
3answers
44k views

Optimal values for ServerLimit, MaxClients, MaxRequestsPerChild directives

I'm running a traffic intense site plenty of dynamic content, mostly user-generated. The server is a dedicated one and has a total of 4 Intel(R) Xeon(R) CPU X3210 @ 2.13GHz proccesors. I need to know ...
12
votes
7answers
21k views

How can I disable encryption on openssh?

I'm having performance problems using openshh(server) and putty(client) combination to use a remote webproxy. I'd like to disable encryption and test the results to see if it makes a difference. How ...
15
votes
8answers
13k views

What is the best filesystem for insert performance on PostgreSQL?

I'm curious if anyone out there has done any experimentation or comparisons between file systems and database performance. On Linux, I'm wondering what is the optimal file system for a postgres ...
3
votes
3answers
340 views

Fastest SSL cipher implementation for Nginx if strength is NOT needed?

I have a use case that is the inverse of most: I'd like to implement very weak SSL ciphers in the name of performance, with the option to fall back to stronger ciphers if the client requests it. ...
7
votes
3answers
1k views

Is there a Unix / Linux command to count lines per second from stdin?

I am trying to count the number of SQL queries per second from a log file and I want to do it in real time by pipeing stdout from grep into some command. ( I am doing some performance testing ) I ...
0
votes
0answers
15 views

How do vCores work in Virtuozzo Virtualization?

We are evaluating vServers based on Virtuozzo. The marketing says 2 dedicated Cores 6 virtual Cores /proc/cpuinfo lists two cores. The support told us, that the virtual cores will be used when ...
0
votes
0answers
35 views

CPU usage of server extremely low and webpage load time high?

On a weekday at a time where very few use the optimized website on the server, the time for the page to completely load excluding 3rd party advertisements is about 0.6 seconds to 1 second. Now when a ...
1
vote
0answers
125 views

RAID6 Ubuntu rebuild - how to calculate best parameters for fastest rebuild

I am doing a resync on a RAID6 array and I am looking at some 2 days to complete. I looked here for hints on how to speed it up, but I have, instead, managed to slow it down! HW details are: 10x 4TB ...
5
votes
2answers
661 views

Linux software RAID6: rebuild slow

I am trying to find the bottleneck in the rebuilding of a software raid6. ## Pause rebuilding when measuring raw I/O performance # echo 1 > /proc/sys/dev/raid/speed_limit_min # echo 1 > ...
12
votes
5answers
14k views

Incredibly slow KVM disk performance (qcow2 disk files + virtio)

I'm having some serious disk performance problems while setting up a KVM guest. Using a simple dd test, the partition on the host that the qcow2 images reside on (a mirrored RAID array) writes at ...
0
votes
2answers
51 views

How to speed up (very remote) overloaded server connection

I'm living in France and I need to load a page from a far far away server (still in the same galaxy). "Far" is Canada to me, meaning over 8 000km of internet cable. The problem is, this server is ...
2
votes
4answers
264 views

How to downgrade a 120 Mbit line, to test website speed?

How to downgrade a 120mbit line (our current connection) temporary to a 10mbit to test what our potential clients with less speedy internet are experiencing as the website loads? At this moment ...
0
votes
0answers
43 views

My website takes a long time to START loading

My website takes a long time to start loading. Once it starts there's a 3 second load time which is fine, but it seems to do nothing for 7 seconds first. Can anyone help me to understand what those ...