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

learn more… | top users | synonyms (2)

0
votes
3answers
8k views

How long does it take to rebuild a drive in a RAID 6?

I'm building a 7-disk RAID 6 array on a DELL MD3000 DAS box. My top priority is storage space, so I'd like to use 2TB drives -- but I'm worried about how long it will take to rebuild a failed disk. ...
1
vote
2answers
804 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 ...
2
votes
0answers
16 views

psping to localhost - improve throughput

I'm using following psping command to measure the bandwith throughput for localhost on a physical server psping -4 -b -l 8k -n 20000 localhost:1234 The throughput is around 150MB/s wich isn't all ...
1
vote
3answers
8k views

Trouble interpreting iostat's tps measure

Prelude: I dumped a 5.2 GB database using the mysqldump command. I did this on an underpowered virtual server with only 512 MB of memory. It took about an hour. I'm now reloading that database on my ...
0
votes
2answers
438 views

How is the average seek of disk estimated given a function to move head to n track

How is the average seek time of disk calculated if a function f(x) is given as an estimate of time to move head of disk to n tracks?
0
votes
1answer
810 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
1answer
936 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 ...
3
votes
2answers
469 views

Which part of of a hard drive has the highest throughput, beginning or end of drive?

If I create a partition at the end of the drive does that create the partition on the outside of the platter where the data is passing under the drive heads fastest?
2
votes
2answers
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
0answers
20 views

server cluster design database server and worker [closed]

I have the following infrastructure available: 1 OF SERVER 1 (DBSERVER): Intel® Xeon® E5-1650 v2 Hexa-Core Ivy Bridge-E incl. Hyper-Threading Technology RAM 128 GB ECC RAM Hard Drive 2 x 240 GB ...
1
vote
1answer
301 views

ssd performance against hdd performance

I have two server, one with a SSD, one with a HDD. I've been running hdparm to see the differences, but the results for Timing cached reads and Timing are quite equal/HDD is faster: SSD: Timing ...
12
votes
3answers
7k views

How much overhead does x86/x64 virtualization have?

How much overhead does x86/x64 virtualization (I'll probably be using VirtualBox, possbly VMWare, definitely not paravirtualization) have for each of the following operations a Win64 host and Linux64 ...
31
votes
12answers
22k views

Is virtual machine slower than the underlying physical machine?

This question is quite general, but most specifically I'm interested in knowing if virtual machine running Ubuntu Enterprise Cloud will be any slower than the same physical machine without any ...
4
votes
5answers
21k views

Disk IO slow on ESXi, even slower on a VM (freeNAS + iSCSI)

I have a server with ESXi 5 and iSCSI attached network storage. The storage server has 4x1Tb SATA II disks in Raid-Z on freenas 8.0.4. Those two machines are connected to each other with Gigabit ...
3
votes
6answers
9k 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 ...
0
votes
2answers
49 views

TCP - TAP performance

Linux. Is there a performance loss from using a tap device vs a hardware one like eth0 ? The goal is to create a user space tcp/ip stack and avoid the kernel as much as possible. I would like to be ...
0
votes
1answer
928 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 ...
0
votes
0answers
18 views
1
vote
2answers
986 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
111 views

How to improve the speed of FTP directory listing with proftpd on Debian 7.5?

I install proftpd on a VPS running Debian 7.5 hosted on Linode.com. The server location is in California (US) while I am remoting from Singapore. The server is on SSD and I am using ADSL 100Mbs ...
1
vote
1answer
32 views

How can I speed up PowerShell cmdlets that are using the -CimSession parameter?

As the title says, how could someone speed up the execution of this tiny script? Am I using the New-CimSession that right way anyway? $computers = Get-ADComputer -SearchBase ...
0
votes
1answer
39 views

UFS wedge : “Out of journal space!” - how to tune? (FreeBSD)

I'm running FreeBSD 9.2p13 with UFS and journaled softupdates. Does anybody know how to tune softupdates journal on UFS? There are no suitable information in handbook, man pages or sysctl ...
1
vote
2answers
63 views

Performance Tuning Linux [closed]

Performance Tuning/ Monitoring/Latency keeping in mind I see following 4 items & in each item they are lot of tools. CPU Memory IO Network What I see following tools we do use. vmstat mpstat ...
2
votes
1answer
52 views

Azure IO performance sql server [duplicate]

We are in the process of migrating our on-premises sql server to Azure and I am having trouble with the IO performance. I have created a new D14 instance and attached 16 virtual disks at 100GB in ...
1
vote
1answer
92 views

Got more RAM, site slower [closed]

I was running my site on 256MB of ram with 2 cores and it was running ok, but I decided to upgrade to 1GB and 4 cores but now my site is slow.. I mean it takes more then 22 seconds to load 1 page.... ...
2
votes
1answer
2k 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
74 views

Advice on web server performance troubleshooting is needed

I'm renting a virtual CentOS based server where I have about 5 active sites running. Several months ago I noticed a significant performance degradation in how my sites are running. First symptom was ...
1
vote
1answer
40 views

Apache CentOS Server very slow! Wrong configuration?

I have a problem with server overload on a Apache configuration 8gb of RAM 1and1.com Virtual Server. Server gets extremely slow once it reaches 100+ active users (according to google analytics) during ...
0
votes
0answers
35 views

Packet loss between windows guest and Ubuntu 14.04 host

We are seeing packet loss between one of our Ubuntu 14.04 hosts and a KVM guest running Windows 2008 R2. The loss only shows up at high loads. Similarly loaded machines running 12.04 do not exhibit ...
0
votes
1answer
28 views

Improve openvpn bandwidth Debian 7

I configured openvpn on a dedicated server. Things are working fine but the bandwidth is not as high as it should be given the network specifications : The dedicated server has 250Mbps DL speed and ...
1
vote
1answer
23 views

Read performance of old LTO-2 tape

I have a stack of old LTO-2 tapes, and my task is to save the contents as large binary files on disk for eventual consolidation on newer media. (The contents are in a custom format specific to this ...
1
vote
0answers
42 views

PHP running slow on Plesk 12 Windows VPS, IIS7.5, 6 cores, 6gb RAM

I am having an issue where PHP is running very slow on my Plesk 12 Windows VPS. Its a high end VPS with 6 AMD Opeteron (2.4ghz) cores and 6gb RAM. The server runs Plesk 12 on Windows Server 2008 R2, ...
-1
votes
2answers
55 views

Parallel disk seek with JBOD

I'm looking to build a 80 TB file based storage system. Ideally, I'd like to do this with a large JBOD and one server with a lot of cores. My question is: Will JBOD containers (like Intel's) allow ...
17
votes
2answers
1k views

How are CPU time and CPU usage the same?

In the Wikipedia page for CPU time, it says The CPU time is measured in clock ticks or seconds. Often, it is useful to measure CPU time as a percentage of the CPU's capacity, which is called ...
1
vote
0answers
1k views

MySQL Workbench InnoDB Buffer Usage at 100%, always

The InnoDB Buffer Usage graph is always at 100%. I believe this started to happen when I changed MySQL's temp folder to a much bigger drive, does that make sense? I suppose the thing to do in this ...
0
votes
0answers
4 views

ATTO benchmark read speed slow below 4MB transfer size on 2-way mirror [migrated]

I've set up two Toshiba DT01ACA300 HDDs in Windows 8.1 Storage Spaces as a 2-way mirror formatted as an NTFS volume. Benchmarking with ATTO shows this (volume is only a quarter full of data) ...
0
votes
1answer
61 views

Optimize .htaccess file

I'm trying to optimize my .htaccess file to avoid performance issues. In my .htaccess file I have something that looks like this: RewriteEngine on RewriteCond %{HTTP_USER_AGENT} bigbadbot [NC,OR] ...
0
votes
1answer
851 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
50 views

Tuning Linux TCP for large number of TIME_WAIT

It looks like we have a bunch of tcp connections hanging around on a busy webserver, this is the output from ss -s: Total: 366 (kernel 1037) TCP: 72108 (estab 130, closed 71964, orphaned 0, synrecv ...
2
votes
1answer
888 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 ...
2
votes
1answer
41 views

Performance-wise, is a DNS Slave better to have than two duplicate Masters?

I have two bind9 servers that are not setup with duplicate settings and know nothing about each other. Our CPU usage is sitting around 7% - 10%: mostly bind, which I believe is perfectly in range for ...
7
votes
3answers
2k views

Apache on Win32: Slow Transfers of single, static files in HTTP, fast in HTTPS

I have a weird problem with Apache 2.2.15 on Windows 2000 Server SP4. Basically, I am trying to serve larger static files, images, videos etc. The download seems to be capped at around 550kB/s even ...
0
votes
1answer
33 views

Why is Win Server 2012 slow to read data with RAID 5?

We have new HP 350p server with 4x 900GB 10k SAS disks with RAID 5 (win server 2012). But disks performance to read data is to slow - it's to slow to read big directory structure on disk. Where can be ...
-2
votes
0answers
18 views

How many simple proxy request / second can a current-generation HP DL360 handle? [duplicate]

Does anyone have any figures (or pointers to calculators) to say how many requests / second I should expect to be able to handle with Apache on a current-generation DL360? The requests are HTTP GET ...
0
votes
2answers
69 views

Squid proxy performing extremely slow and sometimes doesn't work at all

I recently installed Squid on my desktop machine for testing purposes. I didn't edit the config whatsoever, and just pointed firefox at the proxy to see if it was working. Pages take an insanely long ...
1
vote
1answer
14 views

slow file server with contradictory values for CPU and CPL in atop

I've got a fileserver (centos 6.3) that slowed down suddenly earlier today. The cluster that mounts it could access other NFS mounts without a problem, but the access to this one was VERY slow. ...
1
vote
0answers
66 views

NGINX using 100% of the server CPU when testing with Blitz.io

I'm facing an issue here and after four days of looking around I decided to ask for some help here, after all a million heads can think a lot better than one. I have a Ubuntu 14.04 server setup with ...
1
vote
0answers
24 views

Improve read performance on ext4 on Centos with software raid1? [duplicate]

I'm running a number of MongoDB nodes on dedicated servers running Centos6. Each machine has two SSDs which I have in Raid1 with two logical partitions: # df -h Filesystem Size Used Avail Use% ...
1
vote
1answer
31 views

Strange Disk Benchmarking results for our storage, how to explain? [closed]

I recently tested the storage we got from our hosting provider. I don't know what raid config or how many disks the storage contains of. I used Atto Disk Benchmark which sends smaller and bigger ...
2
votes
2answers
106 views

Linux virtual memory tuning to workaround disk I/O issue

I am having a problem with a Linux server that it is writing to much to disk, thus I am having a slow response time due to a big IO wait. I already check smart values for the disks and are OK. This is ...