0
votes
0answers
36 views

ext4 vs btrfs performance on SSD array

I am observing something that I cannot explain. I am trying to come up with a good filesystem configuration using HP P420i controller and SSDs. Out of curiosity I have tried BTRFS (still unstable so I ...
0
votes
0answers
25 views

why is my sort slower with more ram?

System specs below. I recently purchased 2X4 RAM: Corsair XMS3 8 GB (2 x 4GB) 1333 MHz PC3-10666 240-Pin DDR3 Memory Kit CMX8GX3M2A1333C9 I already had 2X2 in there for a total of 12GB: Corsair ...
0
votes
0answers
9 views

Why does top and Google Compute Engine give me two totally seperate cpu % values?

So to preface this, I haven't done much in Linux since a decade ago when I was in college, so I may just be doing something stupid. However, for this project I am working on I'm performing a load ...
0
votes
0answers
27 views

What is fastest way to backup a disk image over LAN?

Sometimes I boot sysrescd or a similar live linux on a PC to backup the hardrive over local network to my server. I noticed many times, that the transfer speed is not optimal (slower than HDD and ...
0
votes
0answers
9 views

Rail's FileStore with Linux Disk Caching or RAMdisk?

I have a Ruby on Rails application that stores it's catched files on the filesystem (Rails file-system cache). I was thinking about changing to memcached Store, but a short test shows it isn't a big ...
-1
votes
1answer
19 views

How do I optimize eSATA performance in Linux?

I experience very slow eSATA performance. Around 5 mb/s on a disk that easily handles 150-200 mb/s. Do I need to enable some setting or module in order to speed it up? The disk is a 4 TB disk and the ...
0
votes
0answers
28 views

Linux MD software raid stripe cache size

From what I can piece together the /sys/block/md0/md/stripe_cache_size is for raid5 and 6 set at a very low default value to avoid starving machines for memory. By increasing this value you can get a ...
0
votes
0answers
38 views

How to force the Linux kernel reclaiming cache memory rather than using swap?

I have a PostgreSQL-driven web service on two Debian servers, one a vhost running Linux kernel 3.2.0-2 with 2GB RAM and the other a dedicated server running Linux kernel 2.6.26-1 with 6 GB RAM. ...
0
votes
0answers
29 views

Error on ubuntu server testing - “fio: first direct IO errored.”

I'm working on a VM to test caching algorithms. The tool I've chosen to push IO is fio (click for HOWTO) given its flexibility. What I don't understand is why running on this ubuntu server 14.04 image ...
1
vote
0answers
37 views

Linux: What is causing high interrupt activity for IRQ 23 (ehci_hcd)?

I run gkrellm to monitor my workstation. Total CPU usage usually runs 0-1% at idle; when there is activity, it's usually cyan-colored (user space). It was running clean this morning. A couple hours ...
-1
votes
1answer
35 views

Investigating linux server slow down

We have a code build server, fedora 13, which was working at medium speed for 4 users. Speed means building a code branch took 1.5 hrs max duration. It was having one quad core, 8gb ram, 200gb hdd. ...
0
votes
0answers
13 views

Page cache flushing behavior under heavy append load

I'm trying to understand the behavior of the Linux pdflush daemon when: The page cache is initially pretty much empty There is a large amount of free memory The system starts undergoing heavy write ...
0
votes
0answers
58 views

Does EnhanceIO supports TRIM on SSD?

Does EnhanceIO supports TRIM on SSD? Or it has own implementation of similar technology?
0
votes
0answers
19 views

Is there a way to run a job exclusively on a chip?

We've got a bunch of large (1TB+) NUMA machines at work and have been getting a lot of noise in benchmarking. We've noticed that run times for our application are very consistent from one run to the ...
0
votes
0answers
31 views

Groovy performance on Linux machine

I have a problem when I start Groovy on one of my Linux machines - it takes about 30 seconds to execute very simple command: groovy -e "" if I run strace on it, here is what I see where it stops ...
0
votes
0answers
16 views

Filesystem vs Object Store

Few months ago I created a PHP storage service, that serves as a bridge between our filesystem and web applications via its REST api. File metadata and file path (and "clustering" per storage type) is ...
0
votes
0answers
22 views

How to estimate the behaviour of a specific process in a non-ideal world?

I am trying to estimate the performance of a specific program (let's call this program as P) that is running on multi-core Linux computer. Currenlty, I'm using tools like perf, top, mpstat, iostat, ...
0
votes
1answer
260 views

Grunt on virtualbox is extremely slow when editing files from shared folder's host machine

My setup consists of a virtualbox running Linux Mint 16 Mate as the guest and Windows 7 as my host. I am running bridged network types although this problem occurs on any network type I choose. I am ...
0
votes
2answers
97 views

Ubuntu 13.10 - make eth0 or wan0 interface upload/download into slow motion for testing software

I have a software where i need to test by making some low speed internet, very limited upload/download, after some time auto disconnect and reconnect such scenarios. I have found that i can try wanem ...
4
votes
1answer
171 views

High I/O system hanging

I have a Fedora 20 box that i'm trying to import a massive amount of data in to postgres on (billions of rows). System spec: 16GB RAM, 6 core 3.2 ghz, 500GB RAID0 PCIe SSD Everytime I/O load gets ...
0
votes
0answers
37 views

Will Linux select the fastest CPU in a SMP system

In a system with for example two physical CPU's, four cores per CPU. If one physical CPU is slower (lower clockspeed, other model) will the Linux process scheduler be smart enough to migrate a high ...
1
vote
0answers
246 views

LSI SAS 2308 MPT2SAS Linux Read/Write performance

LSI SAS 2308-8e (6Gb/s per Lane) PCIe 3.0 card. Average Read/Write Raw performance for 4 SSDs is very low around 430 MB/s (Expected 2 GB/s).I am having Intel Core i3 with quad cores and 4 GB RAM. ...
0
votes
0answers
17 views

Need an application that takes a few seconds to test some speed up techniques

there is this ARM9 SAM9G25 embedded device, which I like to improve its performance. I'm using Buildroot 2013.10 to generate the bootable Linux 2.6.39 images. There are some methods I'd like to apply ...
0
votes
0answers
153 views

Very slow loading gifs on Linux/Mac OS X

I've tried a lot of browsers on windows, linux and mac os x. Same gif-pages that loads pretty fast on windows loads very slow on Linux (like 30+ seconds for page with 5 gifs). For example - tumblr, ...
0
votes
1answer
151 views

Linux benchmark SSD vs HDD

I wonder if there is any performance difference when using SSD as the main Hard drive rather than mounting it to be used by different applications on the server. For example using a command line ...
4
votes
0answers
164 views

How do I evaluate an SSD caching solution for home desktop use?

I've got a 30GB SSD that I would love to start using as a cache for my larger HDDs. I primarily want to improve apparent performance for general desktop use. I do the occasional massive DB migration ...
2
votes
1answer
133 views

Can a kernel that supports multi-core reduce cpu overhead, reduce cpu overheat

I found only a single core as identified by kernel from /proc/cpuinfo. Therefore I am installing a 686 pae kernel to identify all cores and get multi-core functionality. I read about how a process ...
0
votes
0answers
19 views

Optimal config for VM host

I'm facing a big issue when I start my windows virtual machine. I noticed that there are a heavy disk usage, and in consequence the host desktop os is freezing and I'm not able to get back "commands". ...
5
votes
1answer
119 views

Computers are getting faster, so why isn't the desktop experience? [closed]

In the past 20 years, desktop computers have exploded in computational power, but I feel that the desktop experience has been stagnating at best, and actually gotten slower in some places. What are ...
1
vote
0answers
134 views

Poor write performance on ecryptfs

I did a bit of benchmarking with ecryptfs and dm-crypt, and got some interesting results. All the following were done with a Btrfs filesystem, using dd to copy a ~700MB file to/from a ramdisk with the ...
0
votes
4answers
147 views

How to diagnose why a computer is running so slow? [closed]

Generally, what are some ways to diagnose why a computer is running so slow? To find out whether it is because of insufficient memory, busy CPU, or some other reasons? What are some distinct symptoms ...
4
votes
1answer
122 views

No performance increase on I/O intensive operation after symlink to ramdisk

We have a system that transforms a set of several thousand multi-MB files. After every step in the transform, it writes the intermediate file to disk. The concept is similar to a scratch disk. We ...
0
votes
0answers
28 views

HTTPS POST much slower on VM than on its host

I have a Windows 7 Ultimate (64 bit) host running VMWare Player 6.0.1, hosting a Linux Mint 13 (KDE, 32 bit) guest. Using a Perl script to perform a HTTPS POST operation from the Windows box I get a ...
0
votes
0answers
90 views

Can I enable discards on a LUKS-encrypted ssd drive in RHEL6 (and do I need to)?

I have a RHEL 6.4 workstation, running on a LUKS-encrypted LV residing on a SSD. I found RedHat documentation stating that dm_crypt does not currently support TRIM passthrough, however I also found ...
2
votes
1answer
738 views

Linux SSD Performance with Luks / LVM

I've recently obtained a Samsung EVO 840 1TB SSD as a hard disk replacement for my laptop (Lenovo X220t, core-i5-2520m, 8GB RAM). So far, I'm not impressed with the resulting performance and request ...
0
votes
0answers
48 views

Two SSDs,which are exactly same, but sequential write performance varied widely?

I bought two SSDs,which are exactly same, but sequential write performance varied widely? sdb is the first SSD, sdc is the second SSD, and partitions are same(both sd*1 and sd*2) and the sdb1's ...
3
votes
1answer
715 views

Gentoo LDFLAGS optimizations really needed?

I'm using Gentoo Linux. Here is my toolchain: sys-kernel/linux-headers-3.9 sys-devel/binutils-2.23.1 USE="cxx nls zlib -multislot -multitarget -static-libs {-test} -vanilla" ...
0
votes
0answers
27 views

Does being connected to multiple NFS mounts affect performance

On a Linux 2.6 Kernel box, does it hurt network bandwidth or performance in anyn way to have multiple nfs mounts? I am not hosting the NFS, I am just connected to it.
2
votes
1answer
432 views

Clear cache of virtual machine

I already posted this on StackOverflow, but it was flagged as Off-Topic. Maybe you guys are able to help me. I'm currently doing some database benchmarking on a virtual machine running Ubuntu 12.04. ...
0
votes
0answers
38 views

Should I install multiple network services on single VM?

I have a ESXi installed on Dell Poweredge T110 II. On this computer, I'm runing multiple VM. At the moment, there are multiple network services on multiple VMs. For example: I have DNS,VPN,Git on one, ...
1
vote
1answer
963 views

Performance loss when using WINE? Can windows > Ubuntu really account for it? [closed]

I have been considering a switch to ubuntu and also running a LAMP(Small PHP deployments, mainly for learning purposes) stack over it. Though it is my own personal PC, and i'd also want to run my ...
1
vote
1answer
287 views

RAID 5 degraded performance

I'm currently rebuilding my fileserver, but because of SATA port limitations, I can only use 5 disks at a time. I've remove a drive from my original RAID, so I've been able to create a new degraded ...
0
votes
4answers
340 views

Does 64bit GNU/Linux have better performance?

I had 32bit Ubuntu (with Xfce) and now I switch to 64bit Xubuntu and I'm not sure but I think that 32bit had better performace, but just a feeling. I want to know which one 32 or 64 will give better ...
0
votes
1answer
68 views

Irregular time-delay while deleting files

I have a very general question. I am running on Red Hat Enterprise Linux Workstation release 6.2 (Santiago) in a network where my workstation from time to time needs an annoyingly long period to ...
0
votes
0answers
106 views

slow down in SUSE linux enterprise server

I have run a mongodb process that uses most of the RAM (around 10 GB out of the total 11 GB). But immediately after I stop it, there is a huge slow down (even during the process but that is ...
0
votes
2answers
1k views

rsync slow copy from one disk to another

I got two drives of the same model which are connected using SATA. When benchmarking read speeds using hdparm -t /dev/sdX, speeds of about 160MB/s are returned. When benchmarking write-speed using dd ...
1
vote
4answers
778 views

RAID 6 that can read with least 1000 Mbit/s?

I purchased a Dell PERC 6/i which I expected to be able to read with 1000 Mbps. There is not much to do now, but there are some things I wanted knowledge about for another time. I have configured it ...
1
vote
1answer
3k views

How to optimize Linux Mint performance

I'm running Linux Mint 14 on notebook. This notebook is rather old and really weak. Linux Mint shows better performance than Win7, but newertheless it's far from perfect. What can I do to speed up my ...
1
vote
1answer
956 views

cURL SFTP upload speed only 50% compared to command line SFTP

I need to use cURL to upload some files to an SFTP server, it has to be using cURL because I'll be later using cURL_multi etc to transfer files simultaneously (unless anyone knows a command line ...
0
votes
1answer
363 views

How to to measure and monitor I/O performance

We have a linux cluster with worker nodes sharing a common remote file system. We want to optimize the I/O, in particular when the workers read from the remote fs. The starting point is to measure ...