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

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Logging hurts MySQL performance - but, why?

I'm quite surprised that I can't see an answer to this anywhere on the site already, nor in the MySQL documentation (section 5.2 seems to have logging otherwise well covered!) If I enable binlogs, I ...
8
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6answers
3k views

How can I keep Apache from falling over?

I have a pair of servers hosting a single Magento ecommerce site with moderate traffic (60k page views per day reported from google analytics, I think about 80k reported on the server itself). The ...
8
votes
2answers
3k views

How do you disable the “last accessed” attribute on NTFS/Windows?

Inspired by this answer, I realize I have no idea how to disable the last accessed attribute in Windows to increase performance. If you can, how? I know in Linux you can mount the partition with the '...
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6answers
3k views

What's the fastest filesystem for developer builds?

I'm putting together a Linux box that will act as a continuous integration build server; we'll mostly build Java stuff, but I think this question applies to any compiled language. What filesystem and ...
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7answers
7k views

Windows Server 2008 R2 grinds to a screeching halt during file copy operations

When my Windows Server 2008 R2 machine is performing any large disk operations (copying 10GB files from one drive to another, copying similar file over network, merging HyperV snapshots, compressing ...
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4answers
4k views

Using SSD as disk cache

Is there software for Linux to use an SSD as disk cache? I believe that Sun does something like this with ZFS, though not sure. A quick search provides nothing suitable. The goal would be to put ...
8
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2answers
11k 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 ...
8
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4answers
1k views

IIS Optimization

What kind of optimization (performance or whatever) do you use when going live with IIS (on windows 2003) ? Currently, I use 1 application pool per web site, but I think I can do more :)
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2answers
6k views

Nginx auto minify html output

does anyone know of a way to get nginx (or any other method) to minify html output on the fly? It seems straightforward to me and can shave a few kb off and help speed up the site.
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7answers
3k views

What tips do you have for speeding up (performance of) a MediaWiki installation?

We have a MediaWiki installation and are getting complaints that it is becoming slower. How can we increase the speed / performance? I have one tip (which I'll add below) but I'm really interested in ...
8
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1answer
1k views

KVM/Qemu, Ubuntu: Why do more guests CPUs enhance Disk-I/O rapidly?

We have an Heartbeat/DRBD/Pacemaker/KVM/Qemu/libvirt cluster consisting of two nodes. Each node runs Ubuntu 12.04 64 Bit with the following packages/versions: Kernel 3.2.0-32-generic #51-Ubuntu SMP ...
8
votes
1answer
3k views

Best practices for choosing fs block size on ext3/4?

I never really pay block size much attention but obviously there can be benefits to choosing something other than the default. I am looking for a good "best practices" paper on choosing block size. ...
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2answers
5k views

Troubleshooting strategy for very poor iSCSI/NFS performance

We have a new Synology RS3412RPxs that offers iSCSI targets to three Windows 2008 R2 boxes and NFS to one OpenBSD 5.0 box. Logging into the RS3412 with ssh and reading/writing both small files and ...
8
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3answers
8k views

MSMQ very slow to receive messages

We've got a pretty large MSMQ environment setup which today decided to grind to a halt. (Everything is a VM under vSphere 4.0 Update 1) There are 8 Web Servers which receive data from clients on the ...
8
votes
5answers
689 views

ASP.NET High CPU Bringing Servers to their Knees

Ok, our new build is having 100% cpu spikes on each server at random intervals. For long durations it make the site totally unresponsive - this will be at peak times as people in different countries ...
8
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6answers
522 views

How to grow from single server setup

I'm looking for resources on how to grow our server setup. We currently have one dedicated server with Rackspace in the UK of the following spec: HPDL385_G2_PrevGen HP Single Dual Core Opteron 2214 (...
8
votes
5answers
6k views

Partial-stroking / Short-stroking / Half-stroking Hard Drives?

Could anyone here explain to me what is implied by this term? (I've seen the same thing mentioned with the 3 terms). At first when I read about it, for some reason I understood that it was some way ...
8
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2answers
6k views

Extreme UDP packet loss at 300Mbit (14%), but TCP > 800Mbit w/o retransmits

I have a linux box I use as the iperf3 client, testing 2 identically equipped Windows 2012 R2 server boxes with Broadcom BCM5721, 1Gb adapters (2 ports, but only 1 used for the test). All machines are ...
8
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2answers
2k views

Server CPU's: How much does L3 cache size matter when it comes to virtualization?

Performance-wise, how much does the L3 cache size on Intel Xeon i7 processors matter for virtualization functions? I'm picking out a Xeon 1366 Nehalem/Westmere CPU for a server I'm spec'ing to be a ...
8
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3answers
486 views

Adding CPUs puts MySQL 5.5 (Debian) performance down

I am about to setup a database server (MySQL) in OpenVZ container and I've been wondering how many CPUs I should assign to it. I decided to benchmark it. I compared two OS/MySQL distributions and ...
8
votes
1answer
10k views

How should I tune apache when I see high CPU, but low memory usage?

My CentOS web nodes (LAMP stack) are experiencing high CPU usage but low memory usage. Nearly all of the processes are apache. I know I could just add additional web nodes until my cpu usage becomes ...
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2answers
2k views

Is there a standard way to benchmark a Windows VM performance from within the guest OS?

We are seeing our software behaving unusually at one of customers where it is being run inside a Windows 2008 virtual machine. The host is VMWare ESX Server. The biggest issue I have seen is our ...
8
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3answers
2k views

Load testing wireless LANs

Anyone have any suggestions for methods of load-testing wireless networks for enterprise network deployments? We've got a wide array of different wireless worst-case scenarios to support. rooms ...
8
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3answers
4k views

Postmaster uses excessive CPU and Disk Writes

using PostgreSQL 9.1.2 I'm seeing excessive CPU usage and large amounts of writes to disk from postmaster tasks. This happens even while my application is doing almost nothing (10s of inserts per ...
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9answers
5k views

Linux: How to find out whether the harddrive is causing a bottleneck?

I'm not asking how to find out where a bottleneck is. I just what to know how to check if the harddrive is being used at its limit (and hence causing a bottleneck). Something like top where I can see ...
7
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3answers
26k views

Measure Linux IOPS for a running system

How do I measure IOPS of a running Linux server? I know that the theoretical IOPS of a SATA drive is around 90 and enterprise 10k SAS/FC disk is 180. I want to know how much my running system is using ...
7
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6answers
5k views

SMB claimed to be “slow”

Our company network (which I believe is a windows domain run on server 2008) is painfully slow. A prime example of this is copying files over SMB - listings take minutes, and copying even modestly ...
7
votes
3answers
1k views

How to calculate cost/benefit of hardware expenditures? (move to virtualization, upgrades, etc.)

Preamble: As part of the acquisition of a smaller development company we have acquired a new office. Many people were transferred to head office, but 'new' office will retain a small team of 4-6 ...
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5answers
5k 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 ...
7
votes
1answer
703 views

Why is FileZilla so much faster than PSFTP?

I'm using FileZilla 3.10.3 and PSFTP 0.63 (PuTTY). Can anyone help me figure out why the throughput I get is so drastically different between the two clients? It can't just be a shortcoming of the ...
7
votes
2answers
6k views

In absense of iotop which command is most appropriate for get i/o bounded process

Suggest me best way to list io bounded process. I know iotop is best way to get list but want any alternate option since my system showing a large number of D state process.
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5answers
7k views

Freebsd or Linux? as BGP router over 100mbps

I am building a server to act as a BGP border router for my 100mbps uplink in ISP. I needs these feature: 1) Dual stack BGP peering/routing (at least 100Mbps, maybe more). 2) Potential full internet ...
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votes
4answers
9k views

Gigabit ethernet generally faster than Firewire 800?

If I want to transfer a large file between two computers, which are connected via LAN, would going through the network (setup as gigabit ethernet) be faster than using a direct Firewire 800 connection ...
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8answers
642 views

SQL Server performance triage? [closed]

If you get a call/page about a SQL server performance issue, what do you do first? Start a trace? Pop up Perfmon? Open activity monitor? Each of these are useful tools, but what's your "sequence" of ...
7
votes
1answer
2k views

How can I save the counters’ setup in windows performance monitor

I need a comprehensive and complex set of performance counters in windows performance monitor. At this point every time that I use performance monitor, I have to add the counters, one by one. Is there ...
7
votes
4answers
3k views

Does using SSL cause a significant performance hit?

I'm trying to decide whether to use SSL for a webapp. It doesn't handle credit cards or financial data, but it does store information that should be private for personal/social reasons. There is also ...
7
votes
5answers
9k views

Linux md vs. LVM performance

I am trying to tune my NAS, running openfiler, and wondering why I'm getting relatively poor read performance from 4 WD RE3 drives in RAID 5. EDIT: Please note I am talking about the buffered disk ...
7
votes
4answers
7k views

Performance difference between compiled and binary linux distributions/packages

I was searching a lot on the internet and couldn't find an exact answer. There are distros like Gentoo (or FreeBSD) which does not come with binaries but only with source code for packages (ports). ...
7
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2answers
321 views

Disk latency is growing since a few days ago, with no special change in disk throughput

Here is the disk latency graph of my server. The server has two 5400 RPM 32MB Cache SATA 3.0Gb/s hard drives mounted with software RAID 1 configuration. No special changes has happend in those days ...
7
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5answers
4k views

How to measure disk throughput?

I want to know how many bytes per second can I write to the disk and read from it. How can I do that on linux machine?
7
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7answers
14k views

Slow NFS transfer performance of small files

I'm using Openfiler 2.3 on an HP ML370 G5, Smart Array P400, SAS disks combined using RAID 1+0. I set up an NFS share from ext3 partition using Openfiler's web based configuration, and I succeeded to ...
7
votes
1answer
21k 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. ...
7
votes
4answers
3k views

Experience in migrating from Apache to nginx?

I'd like to get some feedback about a migration From Apache to nginx. My goal is to reduce the memory footprint of the web server. Currently, I use the following modules.features on Apache: multiple ...
7
votes
1answer
5k views

HP DL380 G7 + Smart Array P410i + sysbench -> poor raid 10 performance

I have running system with low IO utilization: HP DL380G7 ( 24gb RAM ) Smart Array p410i with 512mb battary backed write cache 6x SAS 10k rpm 146gb drives in RAID10 Debian Squeze linux, ext4 + LVM, ...
7
votes
3answers
40k views

How to set shmall, shmmax, shmni, etc … in general and for postgresql

I've used the documentation from PostgreSQL to set it for example this config: >>> cat /proc/meminfo MemTotal: 16345480 kB MemFree: 1770128 kB Buffers: 382184 kB ...
7
votes
1answer
239 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 ...
7
votes
6answers
22k views

IO Wait causing so much slowdown (EXT4 JDB2 at 99% IO ) During Mysql Commit

I am writing an indexer, using python, which indexes documents and insert them into Database, Before it was single process but now i made it to multiprocessing with 4 parallel processes running.After ...
7
votes
2answers
4k views

pg_restore taking much longer than pg_dump

I am regularly saving and later restoring a smallish PostgreSQL database, which is used for testing. Its data is updated regularly as a result of tests, then a new dump must be made, and the dumps are ...
7
votes
1answer
11k views

How is memcache distributed?

I've got memcache running on 5 web servers all of which are on the host list in php and which are load balanced on the front end. So since memcached is supposed to be distributed the php client will ...
7
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2answers
579 views

Can I have 2Gbit over 1Gbit Nics [closed]

So this really baffles me. Apparently because 1Gbit can transmit data in both directions simultaneously it should be possible to get 2Gbit of data transfer on a single NIC (1Gbit flow seend and 1Gbit ...