What is the Point of Mirroring?

**shizzzon** · July 3rd, 2007, 07:20 PM

I believe it is RAID 1 that mirrors whatever is wrote on one drive gets wrote to the other for a "backup."

Well, that if you were to purchase both drives at the same time and set them up to mirror...
The drives would have the exact same power-on hours therefore should have the same life expectancy. It may be off by a few days or weeks but still, is that how mirroring actually works? That would mean when one drive fails, might as well replace both because the other should die soon, correct?

Wouldnt it be better to just build a massive storage device that holds, let's say 4 500gb HDs and hook it up to a pc via USB\eSATA(whatever works), and just make a backup once a month or so. If the external device is only powered on once a month for the length of a backup for 1 pc... that external device should last....for a LONG, LONG time bringing me back to, when would one use Drive mirroring?

**GroundZero3** · July 3rd, 2007, 07:27 PM

No not all hard drives are the same, some minor defects, dust, a bump, heat or something can kill a drive faster. I had two seagates that were the exact same size and model. One died while the other ran another two years before i retired it (so it was still working)

The purpose of a raid 1 is a back up solution that only needs two drives. You should replace the dead drive asap so it can be rebuilt and be used in case the other drive dies.

With raid, its not a simple black and white situation. The more the drives you have the different raid solutions you can use.

**shizzzon** · July 3rd, 2007, 07:35 PM

yea, i'm sure 99% of people here know more about any RAId config vs me because i have always been leary bout using RAID.

I know practically all gamers RAID their drives for faster performance, whereas any RAID config will have cons, i just havent found a RAID setup where it's con is still not that bad...

First, there was this post,
2nd - join all drives together for faster performance....
con - one goes down, the whole volume goes with it.(very bad unless you have a backup)
3rd - join all drives together for faster performance + mirror that entire volume...
con - very $$$

I guess for me, data on my pcs is critical so performance RAID may not be a wise choice but i had always considered building that large external device for some time now like i mentioned before. Have it powered off of a separate PSU and have USB ports out the rear to connect to a pc. It would also have approx 4-6 burners for optical backup as well. The idea was first thought being introduced to a DVD duplicator then adding multiple HDs inside for permanent storage.

Of course, a duplicator has no interest in my life but backups do.

**GroundZero3** · July 3rd, 2007, 07:40 PM

How are raids expensive? Most motherboards that are coming out do raid 5 and hard drives are cheap as hell.

Raids are used in professional network environments all the time and have saved alot of data because of the way they work. (granted there is some cons to raid but even with a raid, you have a back up of all your data) Its just good practice.

If you want a reliable raid with little performance hit look into a raid 5

If one drive goes down in a raid 1 or raid 5 the system will still be in working condition. If you have a raid 0 and one drive dies then yes you are correct everything is down, but a raid 0 is used for performance and a back up off line.

**shizzzon** · July 3rd, 2007, 07:49 PM

why i think it's expensive?

because i forgot to do addition, hehe

I usually stick to around half a terabyte of information per pc i operate on. Most information is the same on both pcs as a backup but anyways, i'm over here think i need to buy 4-8 500gb HDs, hehe because that was the next size i was gonna go up to, i use all 250s right now.

just .... dont ask what i was thinkin, i think big so i got the....$$$ thought in my head before realizin what i was thinking, lol

**GroundZero3** · July 3rd, 2007, 08:04 PM

Well they have TB hard drives which are a bit high right now, but give it some time and they will come down.

**Cmptr-Gy-Dv** · July 3rd, 2007, 11:50 PM

I see raid 1 in a home computer, a waist of drive space and time,

You are better off just using backup on a spare drive,

Most people really don't think about the difference between
Backup and storage,

Backup is really only needed if you are changing things constantly,
Like in a corporate environment, like on a server,
For home use, most people are not doing a backup,
They are using storage, for pics, and maybe some documents,
Some programs maybe,

So the loss of the space on one drive that you loose with raid 1 is pointless,

And yes using 1 drive for storage, that drive will most likely last longer
Then the whole computer will,

**Peter M** · July 4th, 2007, 11:07 AM

RAID is always always always about increased uptime, working against random HDD failure.

RAID 1 (mirrored) is the simplest way to keep the system running when one HDD fails.

This is not backup, just system availability. Seemingly related but actually totally different goals.

**Ryan220587** · July 4th, 2007, 05:58 PM

raid 1 is the price you pay for data security. if the information you are storing is really that important, then it's worth the extra hdd purchases to have it secured. i am considering a raid 5 myself soon, and i'm told that this particular raid works best with an odd number of hdds. is this true? i really need to do some more research but it will most likely be using 5 x seagate 250g satas.