Welcome to MHO!
I would like to relay my experiences with RAID 5 and offer my well earned opinions on this storage scheme.
Here is my advice:
#1. Don't do it! Never, ever, ever implement RAID 5 on ANY production system. Save your silly idea of 'saving' money buying less drives for your clients you don't like.
#2. Guarantee - you will lose your data on a RAID 5 Array.
Here is why: the parity stripe is is a calculation of ALL your data - when you lose a drive in the Array the parity stripe has to be recalculated and rewritten on the whole array. what this rewrite operation does is reduce your Arrays i/o by 20% and hammers your drives as all your data gets rewritten to the drives. the stress placed on your drives will make another one of them fail or as more commonly happens a sector will go bad during the write and the rebuild will fail and all you data will be lost.
How I learned this:
I inherited a datacenter that was built on 2003 technology, RAID 5 was all the rage because it offered some protection from drive failure, disk space was viewed as expensive and business was still running on paper.
as the equipment had aged the drives in the 30 raid 5 arrays that I was charged with supporting began to near their mean time between failure ratings (MTBF) this is how I discovered all the issues with RAID 5.
My datacenter is now based on RAID 10. my clients can't believe how fast the system is now.
in doing the research on RAID 5 I discovered there is a group called BAARF
I would like to relay my experiences with RAID 5 and offer my well earned opinions on this storage scheme.
Here is my advice:
#1. Don't do it! Never, ever, ever implement RAID 5 on ANY production system. Save your silly idea of 'saving' money buying less drives for your clients you don't like.
#2. Guarantee - you will lose your data on a RAID 5 Array.
Here is why: the parity stripe is is a calculation of ALL your data - when you lose a drive in the Array the parity stripe has to be recalculated and rewritten on the whole array. what this rewrite operation does is reduce your Arrays i/o by 20% and hammers your drives as all your data gets rewritten to the drives. the stress placed on your drives will make another one of them fail or as more commonly happens a sector will go bad during the write and the rebuild will fail and all you data will be lost.
How I learned this:
I inherited a datacenter that was built on 2003 technology, RAID 5 was all the rage because it offered some protection from drive failure, disk space was viewed as expensive and business was still running on paper.
as the equipment had aged the drives in the 30 raid 5 arrays that I was charged with supporting began to near their mean time between failure ratings (MTBF) this is how I discovered all the issues with RAID 5.
My datacenter is now based on RAID 10. my clients can't believe how fast the system is now.
in doing the research on RAID 5 I discovered there is a group called BAARF
