My experience show, what redundant arrays is not guaranty data safety. No, I’m not forget about backups, but usually, restore procedure can take a lot of time. So to prevent arrays crashing i have write small plugin for Nagios. This plugin, written on Perl, allows you monitor few types of RAID arrays:
Today i have spent two hours trying setup synchronization of my Pocket LOOX with Linux desktop PC. Synchronization still not working, but while looking to ‘dmesg‘ output for debugging purposes i have found some interesting AMD Athlon processor features. I knew about frequency scaling before, but i didn’t know what Linux is also has support of AMD CPU Frequency Scaling. I have experience with CPU scaling only on Intel/Centrino processors.
So, i have found this strings:
powernow-k8: Found 1 AMD Athlon 64 / Opteron processors (version 1.50.4)
powernow-k8: 0 : fid 0xe (2200 MHz), vid 0x6 (1400 mV)
powernow-k8: 1 : fid 0xc (2000 MHz), vid 0x8 (1350 mV)
powernow-k8: 2 : fid 0xa (1800 MHz), vid 0xa (1300 mV)
powernow-k8: 3 : fid 0x2 (1000 MHz), vid 0x12 (1100 mV)
Remember my Centrino experience i have look to sysfs for list of available governors. My AMD Athlon 64 support this governors:
When hard drives in server are extremely overloaded, and a lot of different services (Web,FTP,Databases,etc) work simultaneously, it’s very hard to understand what service exactly cause such load.
Here is simple solution how to track per process IO system load:
Since 5.3-Release, FreeBSD has gmirror utility, which allows you create software RAID1. So if you have some low-end server and you need some redundancy - gmirror is right choice.
RAID1 creation process is _very simple_ and completely described in gmirror(8) man page, but i will post small how-to here.
First of all you need check that you have two identical drives. Second drive may be bigger, but total array size = smaller drive size. You can create RAID1 using this command:
I have a new favorite extension for FireFox - Firefox AS Number
Plugin displays a lot of information including AS Number, BGP Prefix, RIR. Plugin can be very useful for network administrators.
We all living in data age, and data integrity is very important. Usually when you loose data, you loose more than just money.
Yesterday i have issue with broken RAID0 massive. People who own that server store all data on non-redundant massive and didn’t has any backups. They ask me to restore anything from hard drives. Well i had restore a one important database, but all other data (about 120G) was lost. So even if you have redundant arrays, you need to do backups.
Below you can find some useful shell script.