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Displaying posts with tag: Hardware (reset)
dbbenchmark.com – Benchmarking script now available

You can download the first release of the benchmarking script here: http://code.google.com/p/dbbenchmark/

Please read the README file or consult the Support page before running the benchmarks.

Four short links: 1 July 2010
  1. Conflict Minerals and Blood Tech (Joey Devilla) -- electronic components have a human and environmental cost. I remember Saul Griffith asking me, "do you want to kill gorillas or dolphins?" for one component. Now we can add child militias and horrific rape to the list. (via Simon Willison)
  2. Meteor -- an open source HTTP server that serves streaming data feeds (for apps that need Comet-style persistent connections). (via gianouts on Delicious)
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mount: /dev/sdb1 already mounted or /mysql busy

We added a 500GB 7.2K SATA/300 Hitachi Deskstar E7K500 16MB disk to one of our dev servers and partitioned using fdisk and formatted the partition with etx3. When we tried mounting the same, we got the following error :

[root@xyz user]# mount -t ext3  /dev/sdb1 /mysql
mount: /dev/sdb1 already mounted or /mysql busy

lsof didn’t provide any open files that might be linked to this problem or there was any “famd” running. Finally doing the following steps to remove the logical devices from the device-mapper driver helped us fix the problem.

[root@xyz user]# dmsetup ls
ddf1_44656c6c202020201028001510281f033832b7a2f6678dab   (253, 0)
ddf1_44656c6c202020201028001510281f033832b7a2f6678dab1  (253, 1)

[root@xyz user]# dmsetup remove ddf1_44656c6c202020201028001510281f033832b7a2f6678dab1
[root@xyz user]# dmsetup ls

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change accelerator cache ratio

I was given the task of checking the array accelerator cache ratio and see if it was set to optimal levels. Our ideal preference was a read/write ratio of 0/100.

The machine configuration is HP DL180 G5, 2 x Xeon L5420 2.50GHz, 15.7GB / 16GB 667MHz DDR2, 6 x 300GB-15K SAS.This machine was running mysql 5.1.36 using the innodb plugin.

The command line utility to check the controller configuration is “hpacucli”. Navigating using hpacucli is very straight forward.

“ctrl all show config detail” Will give you the entire controller configuration.

=> ctrl all show config detail

Smart Array P400 in Slot 5
Bus Interface: PCI
Slot: 5
Serial Number: P61630K9SW31NL
Cache Serial Number: PA82C0J9SW02H1
RAID 6 (ADG) Status: Enabled
Controller Status: OK
Chassis Slot:
Hardware Revision: Rev D
Firmware Version: 4.12
Rebuild …

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RAID Controllers Cache Management – Missing Features

We all know how important hardware RAID controllers are in today’s data storage performance especially when dealing with large data sets. If we look at the trend from now to couple of years back; they really evolved rapidly with lot of useful features and their usage also grown as most of the new servers [...]

Data Store, Software and Hardware – What is best

Other day we had a small discussion about data stores and hardware; and which one drives the other when it comes to data storage solution, rather it is a hard discussion as both on its own are bigger entities; and one can not easily conclude as it depends on use cases and actually speaking data [...]

Dell MD1120 Storage Array Performance

Here is some file IO performance numbers from DELL MD1120 SAS storage array. Last year I did the same test with HP P800 storage array and numbers were impressive. But when it comes to this high end storage array, few surprises.  Before getting into actual details; lets see the test stats and configuration details. System Configuration:

DELL [...]

Ravelry Runs On – 2010

I guess that it’s time for the 3rd annual “Ravelry Runs On” roundup. The last two were in March 2008 and March 2009.

This year, our traffic increased by 50% to 5,000,000 page views and 15 million Rails requests per day. We made very few changes to our architecture in 2009 but we did add a new master database server after our working set of data outgrew our memory and IO capacity.

This summary is more detailed then the last two and I’ve broken it up into rough sections.

Physical Network

We own our own servers and colocate then in a datacenter here in Boston. The datacenter provides us with a cooled half cabinet, redundant power, and a blend of premium (Internap, Savvis) bandwidth. We do the rest.

I use …

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Four short links: 1 December 2009
  1. Apertus -- open source cinema camera. (via joshua on Delicious)
  2. A Survey of Collaborative Filtering Techniques -- From basic techniques to the state-of-the-art, we attempt to present a comprehensive survey for CF techniques, which can be served as a roadmap for research and practice in this area. (via bos on Delicious)
  3. Drizzle Replication using RabbitMQ as Transport -- we're watching the growing use of message queues in web software, and here's an interesting application. (via …
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Four short links: 4 November 2009
  1. ChipHacker -- collaborative FAQ site for electronics hacking. Based on the same StackExchange software as RedMonk's FOSS FAQ for open source software.
  2. Democracy Live -- BBC launch searchable coverage of parliamentary discussion, using speech-to-text. One aspect we're particularly proud of is that we've managed to deliver good results for speech-to-text in Welsh, which, we're told, is unique. I think of this as the start of a They Work For You for video coverage. I'd love to be able to scale this to local government coverage, which is disappearing as local newspapers turn into …
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