Tuesday, January 20, 2009

Life in a RAID 0+1 Configuration

Dear Friends and Family,

Friends have asked if either of us are planning on taking "extended time off" with Pioneer once they're born (i.e. if either of us going to become stay at home parents). And, the answer, most probably, is no. We both enjoy work. But, more importantly, with the sad shape of the economy, we are each others back up plan.

We live life in a RAID 0+1 configuration.

Huh?

A RAID 0 (also known as a stripe set or striped volume) splits data evenly across two or more disks (striped) with no parity information for redundancy. It is important to note that RAID 0 was not one of the original RAID levels and provides no data redundancy. RAID 0 is normally used to increase performance, although it can also be used as a way to create a small number of large virtual disks out of a large number of small physical ones.

Translation: Neither of us brings home a huge paycheck. But the two of us combined bring home enough to make life comfortable for the both of us. That's life in a RAID 0 configuration.

A RAID 1 creates an exact copy (or mirror) of a set of data on two or more disks. This is useful when read performance or reliability are more important than data storage capacity. Such an array can only be as big as the smallest member disk. A classic RAID 1 mirrored pair contains two disks (see diagram), which increases reliability geometrically over a single disk. Since each member contains a complete copy of the data, and can be addressed independently, ordinary wear-and-tear reliability is raised by the power of the number of self-contained copies.

As a trivial example, consider a RAID 1 with two identical models of a disk drive with a 5% probability that the disk would fail within three years. Provided that the failures are statistically independent, then the probability of both disks failing during the three year lifetime is 5% squared.

Translation: Both of us bring home enough of a paycheck that we can stretch it to make ends meet. We can live on one paycheck if needed. So, if there's a 20% chance of either of us losing our jobs (20% squared is 4%) there's a 4% chance of both us us losing our jobs, assuming the one who lost their job doesn't look to find a new job - much better odds than 20% with only one of us working. That's life in a RAID 1 configuration.


Cheers!
mouse

PS: Sorry, the inner geek in me couldn't let go of the analogy - especially with several close friends at different points on the job search spectrum from just found out they were laid off to looking for a new opportunity to looking to launch a consulting role.

PPS: Source: en.wikipedia.org

1 comment:

Trixie said...

omg - having RAID/vpr flashback! xoxox