to Raid0 or not to Raid0

[Liam Carlin]

im using just normal sata hdd's and im wondering if i should raid or not? what are the pros and cons? also correct me if im wrong but a raid hdd is different to a sata and also how will it benefit me when im using prem and AE?

and also considering setting a scratch disk. also do these file up? and if they do then what would i do? just get another one? or clear it? thanks for your time and help.

:-)

[Harm Millaard]

Liam,

RAID is short for "Redundant Arry of Independent (or Inexpensive) Disks". There are various Raid levels and they differ in the degree to which they offer redundancy and speed advantages. Some raid levels are based on mirroring, where an exact copy of data on one disk is copied to a second disk. Mirroring is useful if the data is very valuable, because if one disk fails, there is always an exact copy available to restore the data. Striping is another form of storage, here data is divided across several disks. Thus leads to speeds advantages, since the data can be written to or read from multiple disks at the same time. For a good understanding of Raids, look it up on Wiki or look at: http://www.acnc.com/04_00.html

The disks used in a Raid are normal disks. SATA, PATA, SCSI, SAS, whatever.
If you want to use a AID0 (No R in here, since the redundancy is lacking) you will achieve two things. It will nearly double the disk performance and make Windows see a doubled capacity of the disk(s). So, if you have two ordinary SATA 400 GB disks raided together in a Aid0, windows will see the capacity of the disk as 800 GB (2x400). If you use three disks in the array, capacity is seen as 1.200 GB and performance is nearly tripled over a single disk.

However, the biggest dis advantage of a Aid0 is the lack of redundancy. We all know that disks sometimes fail, and usually at the most inconvenient time. We try to avoid the risks of a drive failure by making backups or Ghost images. In a Aid0 if one drive fails, you lose all the data on the disks in the array. If you have two disks in the array, your risk of losing data due to disk failure is doubled, with three disks it is tripled.

My personal suggestion would be to use a AID0 for scratch, previews and pagefile, and use either Raid3 or Raid5 for media.

Hope this helps.

[James Harring]

I'd concur with Harm's assessment.
Because we are dealing with large files that tend to be problematic to backup, I'd recommend your "workspace" where the files you wish to edit reside be on a RAID-5. Try to use identical drives to ensure even performance.

This allows you to replace a failed hard drive with minimal chance of data loss. Technically it is slower than RAID-0, and faster than mirroring, but it's not significant. As a network manager with a fleet of over 500 PC's hard drive failure is a weekly occurance.

While Raid-0 (two or more drives joined to make one big drive) is fastest, I wish to impress if you lose one of the two drives means ALL data is lost on both drives.

Final note - before putting the unit into production, practice creation rebuilding and deleting RAID before you put any important data on it to get comfortable with the process.

[Martin Chab]

The final note of James:

Final note - before putting the unit into production, practice creation rebuilding and deleting RAID before you put any important data on it to get comfortable with the process.

Is an excellent advise.
I remember the fisrt time I had to rebuid a RAID full of data and the hard time I had.

[Harm Millaard]

Originally Posted by Martin Chab

The final note of James:

Final note - before putting the unit into production, practice creation rebuilding and deleting RAID before you put any important data on it to get comfortable with the process.

Is an excellent advise.
I remember the fisrt time I had to rebuid a RAID full of data and the hard time I had.

I quite agree that it is very wise to get acquainted with the software. However, rebuilding only applies to non-Aid0, since Aid0 lacks the redundancy to enable rebuild. In the case of Aid0 it is all or nothing, it works or everything is lost. For Raid5, rebuilding is the best thing about the redundancy. I had a 6 disk raid5 array and had intermittent problems with two disks. The redundancy allowed me to first exchange one disk and do a rebuild, then exchange the second disk and rebuild again. This was on a server, but rebuilding allowed me to continue without losing work.

[Liam Carlin]

Thanks guys. you have broken it down to the simple terms that i like! io know have a better understanding of whats raid is and what will benefit me.

Also i have to say thank you for answering a question i forgot to ask and thats about backing up data. ive been a little unsure of this but thanks to Harm pointing it out! it all makes sense! im going to be doing a lot more reading on raid, AID0 etc.

but the questions that pop to mind are the usual. which hdd;s do you recommend for scratch and also storage. i think sata is the way to go.

Also the last question is. what do you mean by building a raid drive? is this how it is partitioned? and also do i need a program to do this?

Thank you very much for you time!

[Steven Gotz]

I use a 10K drive for programs, and two 250GB 7200 SATA drives in a RAID0 configuration for media. I have a third 250GB 7200 SATA drive for a scratch disk.

The advantage of RAID0 for me is that it allows me to layer multiple tracks of HDV material without having the drive speed be a bottleneck. I never need RAID0 until I started using Cineform AVI to edit with. The file size is about 3 times that of regular DV.

In my opinion, it is easier, and cheaper in the long run, to back up captured media after a capture session using an external SATA drive (eSATA). Or, even a simple USB drive. I don't worry about mirroring my drives because I save copies of my captures, as well as regular copies of my project files.

Maybe it is just me, but I only capture in big chunks of time. One day I capture and it might be a few days before I do it again. This gives me plenty of time to use a cheap drive to back up my media.

Just my $0.02

[John McGinley]

I'm on board with Steven's method. I have a RAID-0 I use for performance and have a separate 500GB USB drive for backup. I use AllSync to keep my files up to date. I set it to sync when I'm done for the night. I like that I can define which directories I want to back up, because I really don't need the conformed audio or preview files Premiere generates. Obviously you need to actually do it, but if it becomes habitual the worst that happens is you lose a day instead of a whole project.

Also it was mentioned that two 500GB RAID-0 striped drives would make 1TB, that of course is incorrect as the RAID info takes up some space.

[Harm Millaard]

John,

You are right that a raid entails some overhead, but that is far less than formatting a drive, mostly less than 1%. Furthermore take into consideration that disk suppliers have a nasty habit of using 1.000 as the number to calculate capacity instead of 1.024. Usually a '500 GB' disk does contain only 488 real GB's, so it seems that the overhead you alluded to is negligent in comparison.

[Liam Carlin]

Which Hdd's would you recommend me to get? im after 2 500's so as i have one for backup. any suggestions? should i just stick with western digital? any drives to stay away from?

Thanks.

[Harm Millaard]

Seagate 7200.10 come to mind, but you could have a look here:
http://www.storagereview.com/comparison.html

[Liam Carlin]

Thanks for the link Harm :-)