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

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1
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0answers
34 views

SMI generation / detection in GRUB / real mode vs. in Linux

I'm trying to get an idea of the frequency and duration of SMI events on a Supermicro X10SAE C226 board (2.0a BIOS) with E3-1245v3 Haswell CPU. The Intel BIOS Implementation Test Suite (BITS) SMI ...
0
votes
0answers
177 views

Strange ASP.NET Queue Performance Counters Behavior?

We have an ASP.NET 2.0 site running in classic mode. I am seeing very strange behavior in the performance counter values. Perhaps these are bugs (I've been all over Google trying to verify this, ...
2
votes
3answers
513 views

Mysql crashing, oom-killer, out of memory, tuning issues?

I just moved all of my websites to a new server with 4GB RAM. Almost immediately, mysql started crashing, and at one point, didn't reboot which caused a major outage (since I didn't notice until ...
0
votes
1answer
91 views

How to measure TCP connection time in Linux

I want to measure the overhead in creating a TCP connection. I know of many tools like hping and netperf, but they seem oriented at measuring latency. I want to know how long the 3-way handshake ...
-1
votes
2answers
70 views

Count of Unix users: how many is too much? [closed]

I know about Postfix MTA configuration concepts: there's tree of them and the last one is most-appropriate only because it doesn't require new Unix user to be created for new mailbox creation. From ...
0
votes
1answer
217 views

Install Winsat on server 2012? Windows System Assesment Tool

I use winsat disk to see my disk read / write speed windows 8 and it works great: cmd : winsat disk -drive c Can this be used on windows server 2012?
1
vote
1answer
413 views

Centos running Apache Tomcat keep getting “java.net.SocketException: Too many open files”

We're running Apache Tomcat 7.0.41 on CentOS 6 with java version "1.7.0_21". We were getting a lot of too many open files errors so I did some research. The consensus was that it was to to with the ...
5
votes
2answers
1k views

Why would Linux VM in vSphere ESXi 5.5 show dramatically increased disk i/o latency?

I'm stumped and I hope someone else will recognize the symptoms of this problem. Hardware: new Dell T110 II, dual-core Pentium G850 2.9 GHz, onboard SATA controller, one new 500 GB 7200 RPM cabled ...
-4
votes
2answers
106 views

How can I optimize my ajax calls to deliver at 60ms.

I am building an autocomplete functionality for my site and the Google instant results are my benchmark. When I look at Google, the 50-60 ms response time baffle me. They look insane. In ...
3
votes
2answers
301 views

Best practice on Linux servers and CPU/power throttling?

I am running a couple of Debian 6 (2.6.32) and 7 (3.2) Linux servers and all of them have energy saving settings enabled in their BIOS. Furthermore Linux shows that the CPUs are throttled if the ...
3
votes
1answer
201 views

Nginx + unicorn + spdy + performance testing

I have a ruby on rails website that is hosted on unicorn webserver behind a nginx reverse proxy. I want to evaluate if using spdy will enhance my performance under this setup. Specifically, I need ...
0
votes
1answer
79 views

S/W RAID6 and 4k sector format — slow resync

I'm looking for reason why Linux software RAID-6 re-sync is much slower than I expected. I have used 6 WDC WD40EFRX HDDs (with 4k physical sectors) to create RAID-6 array. $ sudo mdadm -v -C ...
0
votes
2answers
107 views

How can I find my peak bandwidth usage over a period of time?

I am about to change Dedicated Server providers. My current provider says the uplink is 500M. The (potential) new host offers by default a 100M uplink and charges an extra $100/Month for a Gigabit ...
0
votes
4answers
946 views

How to explain to users the difference between Xeon and i7/Consumer CPU [closed]

I know that these 2 CPUs, given the same clock speed are still different due to many different factors, but realized I didn't really have enough knowledge to explain it clearly. I assume caching and ...
-2
votes
1answer
87 views

Streaming Server Network Performance [duplicate]

I have server Linux based on centos 6.5 final 64bit , ram 128 G.B dual E5-2650 processor Hard disk : 4 SSD Hard disk RAID-5 Network Speed 1/Gbps Bandwidth Speed 500/Mbps up to 3/Gbps My ...
0
votes
0answers
186 views

On a system with 64GB mem the Linux Buffer run full while copying with dd to dev null and io stops till manual drop_caches

I am running a server with linux software raid 10. It is a dual CPU system with 64GB Ram. 2x16GB dimms related to each of the CPUs. I want to use dd to backup kvm virtual machines and run into a ...
2
votes
2answers
914 views

Windows Server 2003 r2 vs 2008 r2 - Performance for SQL Server [closed]

First off, I'm not a sys admin, just a programmer frustrated by poor server performance… We’re currently running a VM (I believe the host is Win Server 2008) on a newer E5-2650 CPU, 24 GB RAM, at ...
0
votes
0answers
16 views

How to compare and state performance on virtual server instance?

I want to report performance statistics about an algorithm that runs on a virtual server instance with Ubuntu on it. I measured runtime and maximum memory usage but I want to give a statement about ...
2
votes
2answers
402 views

Is there anything I can do to decrease waiting time for my static http requests (in chrome's network panel)?

I am running amazon aws ec2 micro instance on Ubuntu 14.04 with apache 2.4.9. The reason for having this instance is just to test and to solve some bugs before rolling up the project. Currently there ...
2
votes
2answers
266 views

Azure IO performance

We have a number of Windows Server virtual machines that we use for .NET and Java development and QA. I find Azure attractive for the obvious reasons but mainly for the opportunity to reduce ...
0
votes
2answers
142 views

Debugging slow transfer rate from server

I'm trying to explain this as simple but documented as possible. This is not exclusive to this server or my current ISP. I've seen the same exact issue over the years while being with different ISPs ...
10
votes
2answers
341 views

Do unused application pools in IIS affect performance?

Due to a major update in our architecture, we now have a few unused application pools under IIS (there are no web sites mapped to them). I understand how it can a good idea to remove them just to ...
0
votes
1answer
91 views

Ignore utm_* values with varnish?

Can I 'ignore' query string variables before pulling matching objects from the cache, but not actually remove them from the URL to the end-user? For example, all the marketing utm_source, ...
1
vote
2answers
525 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 ...
1
vote
0answers
50 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; ...
0
votes
2answers
170 views

Trying to find bottleneck… 60k onsite visitors

I know this will be hard, but I'm willing to try the Q&A route. I have a Wordpress site that currently has 60,000 visitors on the site at once. I'm using an EC2 m3.xlarge, php/php-fpm 5.5.10, ...
3
votes
1answer
185 views

Filesystem performance degraded during RAID rebuilding

So quick question - our RAID6 array is currently rebuilding and there is a VERY noticeable filesystem performance hit (home directories are NFS mounted on the array). I'd sort of expect that, given ...
4
votes
1answer
243 views

Mail Server Storage Backend: Filesystem VS Database

I am trying to compare mail server software to decide which to use at the ISP where I work. I'm confused mainly about which storage backend is better for such use (again, at an ISP, i.e expected large ...
4
votes
6answers
448 views

When is it time to add more cores to your virtual server? [closed]

I have a Linux (RHEL 5.8) server with Java 7 and Tomcat 7. The performance is poor, and I am pretty sure it's the DB queries that are slow. We have 2 cores right now, and load average never exceeds ...
3
votes
1answer
151 views

iozone: 5 concurrent threads random read of 300K blocks does more ops/s than using only one thread, what could be the underlying reason?

The partition is in RAID1 using software RAID. Command line used: iozone -s 190g -r 300k -O -b test_file OPS Mode. Output is in operations per second. ...
0
votes
3answers
143 views

Linux: Get information/stats about storage network

I want to know as much info as possible about the SAN a linux server is connected to. What commands will give me the most comprehensive view? Simply knowing the WWN of LUNS doesn't do much for me. ...
0
votes
2answers
34 views

Distributed LAMP vs DB and Web Server same box

We have a very read heavy semantic web (RDF) application which is RHEL 5/Apache 2.2.3/Tomcat 6/Java 6 on one Server, and MySQL 5.1 on another. Apache and MySQL are backported Red Hat repo stuff, so ...
1
vote
0answers
312 views

apache performance static file

I have a fairly low-budget VPS (1GB RAM + 2 CPU's) to run a few (5 - 10) different small websites (both static and dynamic). These websites have (very) low traffic (average of 500 unique visits for ...
3
votes
2answers
140 views

Intel Xeon E7-4807 vs Intel Xeon X5690

We replaced our main line of business server with a new one. The old server had dual Xeon X5690s in it (2 generation old chip), the new server has quad Xeon E7-4807s. We expect processor performance ...
0
votes
2answers
137 views

Logging detailed network activity on Windows Server 2008

One of my clients is experiencing internet delays and outages within their small network. They've verified with their cable company that the issue is not related to any cable company outages. The ...
11
votes
4answers
3k views

Why is 1 of my 24 CPUs Pegged at 100%?

I have an HP ProLiant DL380 G7 system using 2 6-core CPUs, with Hyper-threading enabled, for a total of 24 logical CPUs (as seen by Windows). When running our application, total system CPU ...
0
votes
0answers
346 views

Optimizing disk performance on KVM VM configuration

I have a KVM host server running Ubuntu 12.04 LTS, bare bones installation with only KVM installed. The server has an 8 Core Intel(R) Xeon(R) CPU E3-1230 V2 @ 3.30GHz CPU with 32GB of RAM and SATA ...
0
votes
0answers
68 views

when and how to appropriately use /proc/sys/vm/drop_caches

You can clear page cache with /proc/sys/vm/drop_caches. Can someone provide a practical explanation of how this works, when as a sysadmin you would want to do this, how to determine if your system ...
3
votes
3answers
212 views

Can a Hyper-V machine be made slower and/or emulate a slow network connection?

I need to reproduce an issue with a client-server asynchronous communication (a bunch of JavaScript AJAX vs. an OData api), seemingly caused by some race condition in the calculations when the server ...
1
vote
1answer
89 views

can Iowait cause significant RAM consumption increase

I have a node.js process running continuously on a linux EC2 instance, it extracts data and stores it in mysql. Some reads are also performed on the database. The process can run well during hours or ...
1
vote
1answer
939 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 ...
1
vote
1answer
184 views

upgrade/reinstall vmware vsan from beta

Being a VSAN beta tester I decided to upgrade to GA version as VMWare suggests for production sites. They say, it is not possible/supported to upgrade from beta to GA version, and I did not upgrade, ...
0
votes
0answers
108 views

Block requests based on hostname

Has anyone used this module in their Nginx setup? If yes, I would like to know about it's performance. How much would it affect the response time etc. https://github.com/flant/nginx-http-rdns The ...
0
votes
1answer
531 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 ...
2
votes
2answers
232 views

performance tuning vs understanding a memory leak?

I've read just about every blog post and serverfault answer relating to this, but have seen absolutely zero improvements to the server's CPU or Memory usage so I feel like I'm missing something. At ...
0
votes
1answer
63 views

size of extent on LVM2

in LVM1 there was a limit of 65k extends. So size of extent had to been chosen carefully between wasted space on partitions (to big extent) and maximal possible size of logical volume (too small ...
0
votes
1answer
75 views

Best way to optimize site speed for a large traffic website? [closed]

I'm currently managing a Website for a client of mine who gets about about 500-1000 visits minimum a day, and this includes Members uploading videos, photos, blog posts and other content. The site ...
0
votes
1answer
166 views

mod_pagespeed own js and css render blocking

My mod_pagespeed gives a lower score because it's own js and css are render blocking. Given that the tool is designed to speed up, not slow down, I don't think this is desired behavior by design. Has ...
0
votes
0answers
107 views

Ubuntu server router - only 50% of upload bandwidth

I've changed my internet connection to 400 mbps download and 400 mbps upload. Real speeds when computer connected directly to optical modem: 421/412 mbps for download/upload. My network structure is: ...
0
votes
2answers
100 views

How do I prevent a website on my server causing the whole server to crash

I have a server with 6GB of RAM and a 6-Core CPU. Number of websites hosted by the server is about 10, but sometimes 2 of them take 100% CPU and almost entire RAM which cause the whole server to crash ...