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

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17
votes
5answers
48k 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
9 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
63 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
451 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
25 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
17 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 ...
19
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 ...
0
votes
0answers
12 views

Make rsync move (not copy) files on local file system [migrated]

Can I make rsync to move large amount of files instead of copying them when on local filesystem? I would like it to behave like improved mv command. I know about --remove-source-files option but ...
11
votes
1answer
172 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 ...
0
votes
1answer
899 views

How to speed up QEMU on Windows host?

We want to run our Ubuntu 64bit web server virtualized/emulated on a Windows 64bit host. Intended use is to distribute the VM to customers who might not have "elevated" or "admin" rights on the ...
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
305 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
12 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 ...
1
vote
2answers
1k 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 ...
3
votes
1answer
1k views

Very poor disk performance on KVM node - mdadm raid10

For a long period of time, i'm experiencing performance issues on CentOS servers that are used for KVM virtualization. I'm running software RAID-10 with 4 disks (Seagate ST2000DM001, 2TB, 7200rpm ...
0
votes
0answers
27 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 ...
0
votes
1answer
1k views

Why is hash join slow in postgresql 9.1?

I transfered my DB from Postgresql 8.4 to new server with Postgresql 9.1. Size of DB is 9.9GB Data directory is situated on ssd 60GB disk. And server has 16GB RAM and 16 proccessor cores. But today ...
1
vote
1answer
942 views

interpreting IOPS these Bonnie++ and iostat results

I am looking to interpret the IOPS from a few runs of bonnie++ using iostat simultaneously and using the benchmarking from this post: Can I determine IOPS on a disk array using bonnie++? bonnie++ ...
1
vote
0answers
118 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
633 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
36 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
254 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
40 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 ...
0
votes
1answer
1k 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 ...
-1
votes
0answers
5 views

VMWare Workstation split vs monolithic disk [migrated]

After some reading of what's available on the internet it seems that all sources state that monolithic disks are faster, and the only advantage of split disk is portability/compatibility with file ...
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 ...
2
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
51 views

RAID1 very slow with LSI card and 2x Samsung EVO 850 drives

not sure if I'm checking it correctly, but here is what I have. Desktop, LSI 9260-8i card, see config below. 2x 500Gb Samsung 850 EVO drives. I also have Samsung 830 drive attached to motherboard ...
1
vote
0answers
8 views

SAS direct dual link connection to an embedded LSI Fusion-MPT controller

This is a hardware question. I have a dual-link SAS hard drive and a Intel S5000XVNSAS motherboard without the drive cage option. Recently, I bought a direct dual-link cable ...
3
votes
1answer
990 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 ...
0
votes
0answers
43 views

PerfMon: Processor Queue Length - Random high spikes

I'm investigating alleged high CPU usage on one of our client's servers. After about 1 business day of "normal" activity, PerfMon is reporting the following values for Processor Queue Length, and I'm ...
0
votes
0answers
12 views

Postgres 9.3 maximal cluster size with streaming replication [duplicate]

First, I quote from https://wiki.postgresql.org/wiki/Binary_Replication_Tutorial: In Streaming Replication, the master and the standby have special processes called the walsender and walreceiver ...
0
votes
0answers
41 views

Server high memory and cpu - no leads

I've been asked to troubleshoot a server hosting our application at a client's facility. The client has complained to us on two separate occasions in the last week - week and a half. In one instance ...
7
votes
5answers
6k views

How can I replay Apache access logs back at my servers to do real world load testing?

I looked at http://serverfault.com/questions/2107/tools-for-load-testing-http-servers but I couldn't see how to replay my own existing logs in any of those tools. I have a bug that only occurs under ...
22
votes
3answers
7k views

PHP: What are the advantages of FastCGI over mod_php?

It was recently suggested to me that I use FastCGI with PHP. Now I went to the FastCGI page and read it but I don't really understand what the advantages are.
0
votes
1answer
931 views

Troubleshooting MySQL Performance Issues

Environment: 1 physical machine 8GB RAM some older Core2Duo CPU 1 HDD Windows Vista 64 bit 1 Virtual Machine 16 GB RAM 2 vCPUs Windows 7 64bit Both machines running MySQL 5.5.28 (64Bit) with ...
1
vote
2answers
1k views

Horrible PHP/MySQL Query Performance On Ubuntu Server 10.04

I just did a clear install of Ubuntu Server 10.04 with the standard LAMP config.. Then I made a small script to test insert speeds into a table with 3 columns. When I run the script on any of my ...
-1
votes
1answer
22 views

Measure traffic of streaming audio/video in whole office

I would like to measure the different traffic used in our office, specifically streaming of audio and video. I'm trying to assess whether there is any affect of people using streaming on our internet ...
0
votes
1answer
1k 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 ...
3
votes
1answer
916 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 ...
3
votes
1answer
5k 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 ...
0
votes
3answers
3k views

Zabbix not collecting data

It's the first time that i install a Zabbix server on my dedicated server (debian 5). But zabbix cannot collect data from the server itself (no remote server, it's installed on the server i have to ...
4
votes
2answers
69 views

How to interpret values of Perfmon counter Hyper-V Hypervisor Virtual processor\CPU Wait time per dispatch

So there is a lot of guidance on the web that advises tracking the values of the Perfmon counter Hyper-V Hypervisor Virtual processor\CPU Wait time per dispatch as the nearest Hyper-V equivalent of ...
69
votes
13answers
15k views

Are networks now faster than disks?

This is a software design question I used to work on the following rule for speed cache memory > memory > disk > network With each step being 5-10 times the previous step (e.g. cache ...
-4
votes
1answer
36 views

mysql hot add memory

Is it possible for currently running jobs in MySQL to utilize memory that's been hot added? It looks like when memory is hot added to the VM the currently running jobs are not utilizing the additional ...
-1
votes
1answer
21 views

Synchronize Staging Server and Live Server [closed]

We have staging and live server at our office. Where Live code and DB changes are far more advanced than staging one.This application developed under php and DB is mysql. Earlier we used to work in ...