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

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11
votes
1answer
5k views

How do I run my PowerShell scripts in parallel without using Jobs?

If I have a script that I need to run against multiple computers, or with multiple different arguments, how can I execute it in parallel, without having to incur the overhead of spawning a new PSJob ...
1
vote
0answers
536 views

XenServer 6.2 Read Only and Slow Disk I/O

I virtualized a datacenter a few months back and we have a pool of 3 HP DL360 G5 servers, each with 32GB of Memory and dual Intel Xeons. Recently we have been experiencing 2 issues, the first of which ...
3
votes
0answers
10 views

Why higher await time for DM multipath device than underlying device?

We have a CentOS 6.4 based server attached to Hitachi HNAS 3080 storage and observed the kernel remount the filesystem in read-only mode: May 16 07:31:03 GNS3-SRV-CMP-001 kernel: [1259725.675814] ...
0
votes
1answer
10 views

Application Performance & Interrupt Affinity

Quoting the RedHat Performance Tuning Guide 3.3.7. Setting interrupt affinity Interrupt requests have an associated affinity property, smp_affinity, that defines the processors that will ...
11
votes
1answer
151 views

Vendor whitepaper says: 5Mpps no prob. I'm already hitting a wall at 120kpps. Where's the bottleneck?

HP's whitepaper on their QLogic (fka Broadcom) NetXtreme II adapters, which includes the specific NIC that I'm testing, states (page 7) that their small packet performance for packets up to 256 ...
2
votes
1answer
25 views

Is there a maximum 'anything' when running a high number of processes on Windows

I have a series of well optimised services written in house using .Net running on many 512GB RAM server (a mix of Xeons including E5-2697 V2 etc). Is there a maximum handle, process, thread count that ...
1
vote
1answer
19 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 in amazon. But when ...
4
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 ...
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 ...
0
votes
1answer
976 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 ...
0
votes
2answers
170 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 ...
0
votes
1answer
29 views

Ubuntu Trusty: virt-manager performance over WAN… 40+ secs freezes

I'm using the virt-manager GUI 0.9.5-1ubuntu3 on my laptop running Ubuntu 14.04 against a server located some distance away (same OS) and getting rather unpleasant performance. Laptop-server pings ...
8
votes
6answers
6k views

Is there a point in using Prelink anymore?

Over the years using various linux boxes, I've gotten into the habbit of using prelink ritually to accelerate load times of applications. However, the benefits of running prelink are negated every ...
2
votes
1answer
30 views

Does SAS server rotate always in it's default speed (like 10K, 15K)

I have some concerns about disk throughput in order to plan my SQL Server deployment. I know from experience that consumer SATA disks sometimes go into sleep mode when not used for a longer period. Do ...
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 ...
4
votes
1answer
929 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 ...
0
votes
0answers
42 views

Slow hard disk speeds on Windows Server 2008

I have already looked at many articles regarding slow read/write speeds on Windows Server, however they either involve Server 2008 R2, 2012, or are related to speeds over the network. I have 5 ...
5
votes
3answers
7k views

IIS: How to tell if a slow time-taken is due to a slow network connection

According to http://support.microsoft.com/kb/944884, "when a large response or large responses are sent to a client over a slow network connection, the value of the time-taken field may be more than ...
8
votes
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 ...
2
votes
1answer
27 views

How much of a performance does using QEMU virtualization incur on Windows?

How much of a performance does using QEMU virtualization incur on a Windows host, when both the host and vm are running the same CPU? Older articles indicate that using kqemu avoided the slow down in ...
1
vote
5answers
3k views

Possible reasons for high CPU load of taskmgr.exe process on VM?

On a VMware virtual machine which has severe performance problems I can see a constant average of 20+ percent CPU load for the TASKMGR.EXE (task manager) process. The apps running on this server have ...
-3
votes
0answers
11 views

API key looks valid, but nothing seems to work [closed]

Trying to set up a API feed so that videos can appear on my blog (www.workwearexpress.com/blog), however, they don't appear using various plug ins. Also, I can't check Google Page Speed from within ...
2
votes
5answers
4k views

How to measure startup time and order of Windows services on boot?

I am not asking how to measure server startup time here. I am wondering if anyone knows of a tool that can measure and show a graph of the startup time and order of all the windows services during ...
1
vote
1answer
335 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 ...
5
votes
2answers
180 views

raid controller data transfer rate

I'm going to buy an 8-port raid controller for which the declared data trasfer rate is "Up to 6Gb/s per port". The declared connectors are "Two mini-SAS SFF8088". The maximum number of supported ...
1
vote
0answers
21 views

Windows Server 2012 Disk Operations Freezing

I've got 2x brand new Windows server 2012 R2 servers. Fresh install. All Windows updates applied. One on a brand-new physical server, and the other in our VMWare cluster. When I try and perform a ...
2
votes
5answers
5k views

Performance gains of putting Windows pagefile on separate partition (same disk)?

I am making a drive image that will be deployed to several computers, and I'm tweaking it for performance. It is a Windows XP image. Considering there is only one hard drive, will the machine gain ...
7
votes
2answers
141 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 ...
13
votes
14answers
11k views

Why would wireless routers become less reliable over time?

I've been curious about this for awhile now. I don't know if I'm seeing a real pattern or not, but having worked with many home office/small office wireless routers for a few years now, I've noticed ...
3
votes
1answer
240 views

High %soft CPU usage during high network load on ixgbe

We have an Intel 82598EB 10GBE NIC. The network load is composed of lot of small sized UDP packets. To simulate a DDoS, from another server we pushed ~100k pps small UDP packet (just some Mbit of ...
2
votes
1answer
46 views

SAN performance too low?

I've noticed my new EMC VNX5200 SAN tends to perform better after "burning in" a partition. By this I mean filling the partition with different junk data and deleting everything a few times. Asked my ...
0
votes
2answers
1k 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 ...
2
votes
1answer
55 views

Are RAID 5 systems suitable for larger disk sizes?

Why is it generally considered that RAID 5 systems are not suitable for larger disk sizes? Is the same true for RAID 6?
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 ...
-2
votes
2answers
42 views

Why sometimes AWS EC2 works really slow?

I do only one thing one this server - encoding videos by ffmpeg. And sometimes it does work ok, sometimes it's really slow. I run the same command just for a test: $ sudo time ffmpeg -i test.mp4 ...
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 ...
7
votes
4answers
3k views

Performance difference between ramfs and tmpfs

I need to setup an in memory storage system for around 10 GB of data, consisting of many 100 kb single files(images). There will be lots of reads and fairly periodic writes(adding new files, deleting ...
1
vote
6answers
7k views

SQL Server Instancing: Should I use multiple instances or databases?

I have a reasonable server connected to a SAN which will be running SQL servers for multiples of the same application. There are no security issues with one application being able to read anothers ...
1
vote
1answer
1k 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++ ...
24
votes
7answers
9k views

Is it OK to run perfmon on production servers? And why?

Or should perfmon be limited to a Dev/QA server with load tests that simulate production activity? I'd like to run perfmon for two days (like Sql Server master Brent Ozar suggests) to get an overall ...
12
votes
4answers
239 views

tcpdump increases udp performance

I'm running a set of load tests to determine the performance of the following setup: Node.js test suite (client) --> StatsD (server) --> Graphite (server) In short, the node.js test suite ...
15
votes
2answers
1k 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. ...
2
votes
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
544 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
34 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
2k 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
107 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
971 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 ...