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

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139 views

Network Performance / SMB-CIFS / Guidance

I'm an IT professional working out of my home office. I'm having some performance problems (NAS file copies) which I'm trying to isolate, using iperf. My question is on iperf. Infrastructure - ...
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0answers
218 views

Sizing of journal disks with Microsoft Storage Spaces parity volume

I'm currently speccing out a new backup server. It's going to be running Windows Server 2012 R2 with Direct Attached Storage, and I'm considering using Storage Spaces rather than using a RAID card. ...
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0answers
58 views

slow copy due to disk write issue

I am trying to copy a file from /backup/ folder to /backup/abc/ and it is taking a lot of time. The copy operation on performed on other server is pretty fast. # df -HP Filesystem Size Used ...
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2answers
39 views

How to meassure disk access [closed]

How can I meassure the disk access on Windows Server 2012? We have some storages attached via iSCI one with SSD and the other not. I would like to compare the disk access speed. In order to figure out ...
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1answer
167 views

Why does a low level format take very long time?

I can write ~100MB/s on a particular 4TB SAS drive when it have a file system on it, but a low level format on this drive took >16 hours. That's ~70kB/s. Since there is not filesystem and only zeroes ...
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1answer
61 views

Poor performance executing “cp -al” over a NFS export

I am in the process of implementing a backup of a WD My Book Live Duo. This device is configured with software RAID0. The backup source directory is the root of the device, and the destination is a ...
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0answers
37 views

Why is my server so slow to accept connections?

I've noticed that my server seems to be very slow to accept connections - i.e. when analyzing the load time using the Chrome event map, it shows that some tasks can spend multiple seconds waiting for ...
2
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2answers
76 views

Lots of major page faults in CentOS

We have a fairly complicated PHP script that's generating a lot of minor and major page faults. $> ps -o min_flt,maj_flt,time,cmd,pid 4686 MINFL MAJFL TIME CMD ...
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3answers
492 views

sudden peak in cpu usage

We are running a 4 node/machine elastic search cluster on 12 core, 96gb RAM, 4 spinning disk machines. under normal operation most cpu usage is user and around 5-10%. Every few days, one of the ...
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1answer
42 views

HDD performance testing over LAN [closed]

Do you know some utility that allow me for HDD performance testing over lan. The issue - I have a shared drive with shared file database. Performance of the database is low and I assume that ...
1
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1answer
169 views

How can I diagnose and speed up slow Linux puppet sync?

I'm running puppet and it functions okay, but it's taking about 15 minutes on a sync without any changes, and it seems to me that this shouldn't take more than a minute or two. Here are some stats: ...
1
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1answer
106 views

MongoDB - DB/collection fragmentation level

I recently had a performance issue with one of my collections. On a whim (and thanks to this article), I decided to try compacting (as written in the official documentation). This worked brilliantly. ...
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1answer
49 views

Is there anyway to find what php scripts consume more resources

I want to easily find load cause, Is there a way to display resource usage for php scripts like this. Cpu: index.php 30% something.php 10% ... memory: index.php 50% something.php 10% ..
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2answers
110 views

Unreasonable performance expectations for RAID 0 performance?

This is my first time building a machine with a hardware RAID card. We bought a Dell T620 with the H710P RAID controller (1GB NV Cache), a 160GB Solid State Drive (SATA Read Intensive MLC 3Gbps), and ...
1
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1answer
71 views

MySQL suddenly taking 2000 ms per request, instead of 200

UPDATE: finally remembered to look at munin, and it seems that one of the HDDs is the root of the problem after all, unless I'm totally reading this wrong. Here's the munin output: ...
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0answers
52 views

SQL Server 2014 Standard 2014 no access and bad preformance

My company looks after a server which is running SQL Server 2014 Standard Edition. The main application database on the server is replicated out to about 20 subscribers. The server has only been in ...
0
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1answer
49 views

Perfmon % Processor Time unbalanced

I am somewhat of an accidental DBA, and I'm troubleshooting a SQL Server box where performance has been notoriously poor (as reported by the customer). I was not involved in the initial planning of ...
5
votes
4answers
3k views

How do I configure RAID 5, especially stripe size, with 24 x 1.2 TB drives for CentOS 6?

For a Dell R920 with 24 x 1.2TB disks (and 1TB RAM), I'm looking to set up a RAID 5 configuration for fast IO. The server will be used to host KVM VMs that will be reading/writing files of all sizes, ...
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2answers
72 views

Very high First Byte Time

A client of mine which I will be completely re-building the site for, is having some major speed issues with the current site. It takes on average 4.4 to 4.8 seconds before the First Byte Time to ...
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0answers
29 views

How to find out what is blocking requests on Apache2

I'm running a website on Apache 2.4.9 that creates thumbnails of images a lot and when users browse the website they create cca 100 requests per page. Thumbnails are returned by PHP script that has to ...
46
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10answers
14k views

How to [politely?] tell software vendor they don't know what they're talking about

Not a technical question, but a valid one nonetheless. Scenario: HP ProLiant DL380 Gen 8 with 2 x 8-core Xeon E5-2667 CPUs and 256GB RAM running ESXi 5.5. Eight VMs for a given vendor's system. ...
2
votes
1answer
41 views

What is the correct way to track and monitor Exchange DB replication “pressure” over time?

I want to determine if some databases are overloaded or unbalanced, and think that looking at the transaction logs created per database over time would tell me which DB is at risk of missing RPO ...
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2answers
894 views

Why is my RAID1 read access slower than write access?

I have done some simple performance tests and it seems that reading from my RAID1 is slower than writing: root@dss0:~# for i in 1 2 3; do dd if=/dev/zero of=/dev/sda bs=1048576 count=131072; done ...
1
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1answer
348 views

6 times slower disk write in RAID10 on Ubuntu 14.04 after rebuild

OS: Ubuntu 14.04 LTS Software Raid 10: 4x120Gb Intel 530 SSDs Initial tests: 1.2 GB/s Write 5.2 GB/s Read I did some tests to check if everything will go alright with a failed disk: I set as ...
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0answers
922 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 ...
12
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7answers
1k views

How do storage IOPS change in response to disk capacity?

All other things being equal, how would a storage array's IOPS performance change if one used larger disks. For example, take an array with 10 X 100GB disks. Measure IOPS for sequential 256kb block ...
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0answers
52 views

sar -b reports much too high statistics, are the I/O counted twice?

On a Linux server sar -b reports much too high read block statistics, sometimes 3.500.000 readb/s peak and around 2.500.000 readb/s sustain, which makes more that 1 gigabyte/s (according to the sar ...
0
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1answer
113 views

pagefile and disk space monitoring on server 2012

I have had a server crash recently because of the disk space. Here is what I have: a Hyper-V 2012 server with 1 win 2012 image physical disk is 500GB server uses 800GB It was OK for half a year but ...
3
votes
1answer
214 views

Upstart: Why two processes when running as a different user?

I want to keep a nodejs app running, so I followed this: http://howtonode.org/deploying-node-upstart-monit and installed Monit and Upstart which have been working perfectly for a couple of months. I ...
3
votes
1answer
195 views

Can rsync display current average speed?

When I'm transferring large quantities of data using rsync, it would be helpful if I could have the average speed up until now at a glance, rather than a bunch of different speeds for each file.
0
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1answer
70 views

Performance Monitor for ASP.Net applications

I have an IIS hosted ASP.Net site which is experiencing timeouts. I would like to be able to monitor it from every angle but I'm not sure where to start with configuring PerfMon counters. Does anyone ...
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0answers
628 views

Server 2012 slow performance on ESXi 5.5

I'm having performance issues with a virtual Server 2012 that is installed on an ESXi 5.5 (HP-ESXi-5.5.0-iso-5.71.3). The hardware server is an HP ProLiant DL380p Gen8. The server 2012 is acting as ...
3
votes
1answer
93 views

Optimal RAID10 configuration for 8 disks and two volumes?

I have an Open-E file server with 8 SAS disks and a MegaRAID 9271-8i controller and I want to configure two logical RAID10 volumes of identical size. One volume has about 66% write access and 33% read ...
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0answers
86 views

actual disk iops and write merging

/dev/sdb has LVM and exposes a single logical volume, dm-0. While writing to dm-0, /proc/diskstats reports: # of writes completed sdb 29646717 dm-0 131315099 # of writes merged: sdb 101668283 dm-0 ...
3
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1answer
35 views

Is it possible to view average system performance/load over time on a default installation of Windows Server?

Without previously configuring collector sets, is there any record of performance metrics kept on a default installation of Windows Server? I have been tasked to evaluate the load on a particular ...
1
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0answers
38 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 ...
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0answers
215 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
716 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
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1answer
150 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 ...
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votes
2answers
71 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
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2answers
283 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?
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1answer
619 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 ...
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votes
2answers
2k 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 ...
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votes
2answers
132 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
345 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
234 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
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1answer
92 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
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2answers
114 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
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4answers
2k 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 ...
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1answer
96 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 ...