software raid

[shazzam1]

Any good documentation on how to build software raid 5 with centos 5

 

[thedaver]

software raid implementation is really a matter of using the installer of your distribution to create the RAID disc. keep in mind a few typical cautions people offer on the subject:

1) software raid is a meaningful resource demand on your system since your core cpu(s) must do all the overhead to manage the raid array - typically the advice is to use hardware raid. this obviously means an investment in the gear, but if you have data whose value justifies RAID5...

2) software raid is difficult to boot from, although many configurations can support it. I recommend that you have an un-RAIDed primary/bootable disk for some of your OS, and then allow the OS to bring up the s/w RAID later in the boot process.

D.E.R. Management - IT Project Management Consulting

http://www.dermanagement.com/

 

[QatQat]

best MDADM tutorial

http://www.linuxhomenetworking.com/wiki/index.php/Quick_HOWTO_:_Ch26_:_Linux_Software_RAID

QaTQat

If I could have sex each time I reboot my server, I would definitely prefer Windoz over Linux!

 

[thedaver]

That article ends with the following stipulation:

Linux software RAID provides redundancy across partitions and hard disks, but it tends to be slower and less reliable than RAID provided by a hardware-based RAID disk controller.

Hardware RAID configuration is usually done via the system BIOS when the server boots up, and once configured, it is absolutely transparent to Linux. Unlike software RAID, hardware RAID requires entire disks to be dedicated to the purpose and when combined with the fact that it usually requires faster SCSI hard disks and an additional controller card, it tends to be expensive.

Remember to take these factors into consideration when determining the right solution for your needs and research the topic thoroughly before proceeding. Weighing cost versus reliability is always a difficult choice in systems administration.

D.E.R. Management - IT Project Management Consulting

http://www.dermanagement.com/

 

[QatQat]

for sure,

it is a given that, where possible and money not being an issue, Hardware RAID is better and somehow easier to manage.

I was jujst trying to answer to a specific question
"Any good documentation on how to build software raid 5 with centos 5 "

and the document at the above link, I think, is easy to follow, yet quite compprehensive.

QaTQat

If I could have sex each time I reboot my server, I would definitely prefer Windoz over Linux!

 

[thedaver]

QatQat, yep no problem with your answer. I was trying to hammer home the point that software raid has some limitations & issues over hardware. I'm with ya! Dead horse beaten.

D.E.R. Management - IT Project Management Consulting

http://www.dermanagement.com/

 

[withanh]

I agree with hardware RAID, but one of the most compelling arguments I've seen for software RAID is rebuilding it. With a hardware RAID, if your RAID controller quits working, you have to find an identical one, even if its years old, you need the same model to bring that RAID back up. With software RAID you just tell Linux which drives are in the RAID and it rebuilds...