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Anto39x · Nov 2, 2012, 08:37 AM

I am hoping someone of you guys can help me.

I'm have QTY 4 x 2TB Western Digital Green Caviar drives and I would like to put them into some sort of NAS or RAID enclosure that would then allow me to use it as an 8TB media hub for all my videos and music.

I already have a 12TB DroboS raid to backup all my work content.... but I have these four drives that were not very good in my Drobo (slow performance) that I don't want to leave around idle.

Currently I stream all my media content through my main MacPro 12 Core via iTunes... but I have alot of other content that I would like to be able to stream also without having to have my MacPro and 30" ACD on all the time.... is there a solution here that would allow me have a standalone hub for this content .

Any suggestions or comments most welcome....?

Regards,
Anthony

jmiddel · Nov 2, 2012, 01:33 PM

OWC has many RAID boxes. http://www.macsales.com/ With the MP you could always add a PCI eSata card for speed.

Waragainstsleep · Nov 2, 2012, 04:13 PM

Get a Netgear ReadyNAS NV+

If those drives are the 20EARS models they are certified for use in one and it has an iTunes streaming client built in I think.

subego · Nov 2, 2012, 04:57 PM

WD Greens are not ideal for use in RAIDs.

If the drive controller finds a particularly difficult sector, it'll take some time to work on it. This isn't a problem in a single drive setup, but in a RAID, the pause can be long enough for the RAID controller to give up and declare the whole drive is bad.

This is one of the things WD has built into the Red drives. It doesn't wait around for the bad sector. It marks it as bad and moves on.

That said, I don't expect you to pitch the Greens, so I have to give you "the speech". My apologies if you've heard it before.

A RAID is not backup. It is more reliable than a single drive, but that is not the same as backup. If you only have one copy of something, even on a RAID, for all intents and purposes it does not exist.

Whew. Sorry about that.

More OT, I would suggest looking into a Synology box.

I would also suggest Waragainstsleep look into them. My ReadyNAS was molasses slow and sounded like a jet engine comparatively.

Anto39x · Nov 3, 2012, 08:29 AM

Thanks Waragainstsleep and Subego for your suggestions... they were originally 20EARS drives but as you mentioned Subego, I had to get them replaced as they failed in my Drobo and they were upgraded to WD 20EARX's.

What I suppose I'm looking is a why of using the other QTY 4 x WD20EARX drives fro other purposes and currently to access my content I have to have my main MacPro system constantly on... so I was hoping this new media box... would be the only think I would have on 24/7 for access to all my media...? would that be possible...?

What is the difference between a RAID system and a NAS system anyways.... or would you have any other suggestion what I should do with QTY 4 x 2TB WD20EARX drives as extra capacity. Whatever I do I still need to have a backup of my content as I wouldn't want to put all my content on this new NAS drive only to have it fail and the data gone.

Thanks again for all your help and suggestions.

Regards,
Anthony

Anto39x · Nov 3, 2012, 08:47 AM

Hi guys...

I just found this new Synology NAS system... it will work with my WD Caviar Green 20EARX drives... would this be a good investment would you think... again... would I be able to access the files from this over wi-fi without having to have my main MacPro system turned on..?

Regards,
Anthony

besson3c · Nov 3, 2012, 10:48 AM

If you have 4 x 2 gig drives, do not build an 8GB RAID-0 array. I realize that these files are probably not all that important to you, but sooner or later one of those drives will go bad, rebuilding that thing will be a PITA and you will lose data.

I would do RAID-5 on those drives if you want to maximize your available capacity.

subego · Nov 3, 2012, 05:07 PM

Originally Posted by Anto39x

Thanks Waragainstsleep and Subego for your suggestions... they were originally 20EARS drives but as you mentioned Subego, I had to get them replaced as they failed in my Drobo and they were upgraded to WD 20EARX's.
What I suppose I'm looking is a why of using the other QTY 4 x WD20EARX drives fro other purposes and currently to access my content I have to have my main MacPro system constantly on... so I was hoping this new media box... would be the only think I would have on 24/7 for access to all my media...? would that be possible...?
What is the difference between a RAID system and a NAS system anyways.... or would you have any other suggestion what I should do with QTY 4 x 2TB WD20EARX drives as extra capacity. Whatever I do I still need to have a backup of my content as I wouldn't want to put all my content on this new NAS drive only to have it fail and the data gone.
Thanks again for all your help and suggestions.
Regards,
Anthony

RAID stands for Redundant Array of Independent (or Inexpensive) Disks.

NAS stands for Network Attached Storage.

If it has more than one disk, it's a RAID. If you access it over your network, it's NAS.

The Drobo, ReadyNAS, and Synology units are both. They are NAS which use RAID.

The important types of RAID are:

RAID-0: All your drives are made into one big volume. This is the fastest, but also the least safe. If one drive goes it's all gone.
RAID-1: Every drive is mirrored to another drive. This is the safest, but is also slowest, and uses the most space.
RAID-5: The compromise. This is what you should use in almost every circumstance. Gives you more free space and is faster than RAID-1, but unlike RAID-0 you can lose a drive and not lose any data.

I really like my Synologys. I have two 5-bay models each with the 5-Bay expansion. One backs up automatically and effortlessly to the other using the built-in software. I don't use it, but they have iTunes server capabilities.

besson3c · Nov 3, 2012, 05:13 PM

RAID 10 is very common and important too... It's, for example, 4 disks pooled together into a big volume (striped) with a 4 disk mirror. It's common because software based RAID 5 is unsafe, you need a RAID card to do it safely because of what is known as the RAID-5 write hole.

subego · Nov 3, 2012, 05:19 PM

AFAIK, not an issue if you have an Uninterruptible Power Supply, which you should.

besson3c · Nov 3, 2012, 05:27 PM

I think it still is an issue, albeit a very tiny one. The battery is intended to perform the last of the writes once power is cut. The UPS just extends how long the machine can stay online with no AC power

subego · Nov 3, 2012, 05:53 PM

You have a pretty ratty setup if you can't get your UPS to trigger a shutdown before it dies.

besson3c · Nov 3, 2012, 07:06 PM

True. It may be a moot point anyway though. I'm not sure OS X supports software RAID-5 anyway, ditto for Linux.

Waragainstsleep · Nov 4, 2012, 06:15 AM

Originally Posted by subego

My ReadyNAS was molasses slow and sounded like a jet engine comparatively.

I think the newer ones are a little better, they changed the chips IIRC. I only suggested it because I know Netgear certifies those WD green drives for use in them. Most makers won't support non-RAID spec drives for reasons already covered here. Also I think there is an iTunes sharing client on them and if its only for movies etc, they don't to be all that fast.

Waragainstsleep · Nov 4, 2012, 06:18 AM

Originally Posted by besson3c

True. It may be a moot point anyway though. I'm not sure OS X supports software RAID-5 anyway, ditto for Linux.

I never found a way to do software RAID 5 on OS X. I looked.

Maybe its built into Core Storage though. If you want to much around in the CLI.

besson3c · Nov 4, 2012, 11:50 AM

Originally Posted by Waragainstsleep

I never found a way to do software RAID 5 on OS X. I looked.
Maybe its built into Core Storage though. If you want to much around in the CLI.

If I were Apple I wouldn't bother to make something that can shoot them in the face available to them.

Plus, I don't know how Apple would verify in the integrity of a RAID-5 setup anyway when HFS+ itself has nothing to provide any integrity. With RAID 1 or 10 it's just a matter of "did this block get copied" or not, and does it have a matching checksum, assuming Apple's RAID implementation (if not simply the FreeBSD one) checks on the latter.

P · Nov 5, 2012, 03:22 AM

There is no software RAID5 in OS X. One could be created by diving below HFS+ into the storage driver, but that's a lot of work for a rarely used feature.

EDIT: I need some sort of parity checking for my mind (also a read cache): Apple has something that dives below HFS+ to do that sort of thing. It is called Core Storage, and we just saw it take center stage as the magic behind Fusion Drive. Apple could add something like software RAID 5 (or checksumming data, like we spoke about in the other thread) to Core Storage if they wished.