purchase suggestions for 5 drive RAID
In an earlier thread, several people kindly helped me make a decision on my future storage needs.
So, I've decided on a 5 bay eSATA RAID with hotswappable drives. I want to set it up this way:
-drive A for "active" projects
-drive B to mirror drive A
-drive C & D striped for high speed use (eg. as scratch disks for PShop, iView and Realviz Stitcher)
-drive E as "archive" disk (as projects on A are finished and no longer "active", they'd get manually moved here to E, and when this drive gets full, I'll pull it, shelve it, and replace it)
(I actually plan to only start with one drive, and to fill it with more as budget allows)
I'm afraid that I need help making a purchase decision. I've found the following, but I'm having trouble determining which is/are the quality product(s):
SilverSATA V: WiebeTech Micro Storage Solutions - SilverSATA™ Series - External FireWire and USB SATA hard drive Enclosure
TrayDock eSATA (4 bay version): WiebeTech Micro Storage Solutions - TrayDock eSATA™ (I know, only 4 bays)
Sonnet Fusion 500P: Sonnet | Fusion 500P - 5-Bay Serial ATA Drive Enclosure with Port Multiplier
MacGurus Burly 5 Bay PM Enclosure: MacGurus:Burly Port Multiplier SATA Enclosures
The SilverSATA seems much more expensive than the others. I don't understand why, does it have some functionality that the others don't?
And will any old eSATA card be ok?
Thanks in advance for any help,
Not only do you need a Mac compatible eSATA card (there are a few available) you need to make sure the chipset on the computer-end supports port multipliers.
Hey mduell, thanks for replying.
I've seen a few cards that state that they're Mac compatible (One from Weibetech, one from Sonnet, and others if I remember correctly), but I'm not sure what you mean by: "you need to make sure the chipset on the computer-end supports port multipliers". Isn't the card the computer-end? (the computer is a G5 dual 2.0, btw).
The TrayDock isn't a port multiplier solution, by the way, each drive gets its own connector (I'm not sure why the newer solutions are port-multiplied, except that it saves cable-clutter). Seems like a competent solution, and the price is right.
Wiebetech offers compatible adapters on their homepage, if you need to find one.
Also, perhaps two smart 2-bay enclosure (SilverSATA II SR) and a one-bay enclosure might also be worth a thought. You could take any Mac-compatible SATA card with external ports.
This way, you'd have a hardware RAID for your active projects disk and your scratch disk.
However, if you want to stick to the five-bay enclosure, you will probably have to stick to the card WiebeTech offers on their website. Normal SATA cards won't work.
Thanks again for the info.
Ok, if I am understanding correctly, the SilverSATA products are hardware RAIDs? (I guess this would explain their greater cost to what I thought were similar products). I'm afraid that I'm really not sure what a hardware RAID could offer me that I can't get with a software RAID (if anybody could point me to a decent FAQ comparing and contrasting the two, I'd very much appreciate it, as all of the RAID discussions I've found so far assume critical knowledge I don't have).
If understand what you're suggesting, I could have one two-bay SilverSATA for what I called drive A and B (A for active work, B mirrored), another SilverSATA two bay for scratch (two striped drives) and a third single-bay SilverSATA as my archive solution. The only advantage this arrangement would have is that I wouldn't be restricted to the WeibeTECH card necessary to run a five bay SilverSATA?
To keep costs down, i've been considering the less expensive 5 bay solutions from Sonnet and MacGurus. I'm assuming now, because of their reduced price compared to the SilverSATA offerings, that these will run as software RAIDs. Can I use the Mac OSX software RAID to configure these two other products the way I want? (A for work, B mirrors A, C & D striped scratch, E for removable archive).
I hope you'll forgive me trying to learn as much as I can, but I'm going to have to buy all this sight-unseen, and I'd be gutted if it didn't work the way I need it to.
No, not all of them are (with the exception of hardware RAID0). In particular the 5-bay model can only do RAID0, JBOD and not even RAID1. I doubt you could configure a RAID0 with only two of the drives, but this is just a conjecture.
So the advantage of the alternative setup I have proposed is that you will have two hardware RAIDs which can be connected to another computer transparently (all they see are external harddrives). This transparency is the reason why IMHO hardware RAIDs are definitely preferable to software RAIDs: everything is done transparently and you can move your RAID from computer to computer and from OS to OS. If you intend to use that equipment professionally, I would definitely go for a hardware RAID solution. My standard resource is on RAIDs is this. (It was written in 2000, but it's still up to date in terms of basic principles and reasoning behind RAIDs.) Take a look here and here as well. Note that at that time, external hardware RAIDs were not as common as we know them today, so there is the additional advantage that you can use the same RAID with several computers transparently.
You can use OS X integrated software RAID to do what you want, but I wouldn't recommend it for a production environment. Not because OS X software RAID is particularly bad/good, but because of the inherent limitations of software RAIDs. A `real' RAID, such as WiebeTech's RT5 or its professional-grade ProSATA SS8 and Apple's XRaid are more expensive, because they offer a lot more. Depending on what you do (in particular, your capacity requirements), you might not need them.
By the way, what do you want to do with the RAIDs? What are your capacity requirements? Then we can also suggest some drives for you. (For instance, if you work with large files, there is no need getting a Raptor for your RAID0, get a large drive instead.)
Thanks very much for the pointer to those FAQ pages, _finally_ a comparison between hardware and software RAIDs! (really, I looked around for something like this myself!).
It seems to me, for my situation, that a hardware RAID isn't going to be necessary. I work alone, and this new storage that I need is going to be permanently connected to my desktop computer (G5 dual 2.0GHz). The only concern is that I'll eventually upgrade my desktop machine to a Mac Pro, and I'm guessing I'll have to wipe all the drives (or just the striped ones, not sure) on a software RAID in order to move it to a new machine. I don't see this as a problem.
I believe that a storage strategy based around a 5-bay RAID enclosure will benefit me in three ways:
1) two drives striped together (RAID 0, I believe) for scratch
2) two drives mirrored for redundancy
3) all in one case (the cable and box clutter I have on and around my desk is getting unmanageable, and anything that lets me reduce that is welcome)
As for my capacity requirements:
1) one working disk of 500Gb is just about right for the projects I do (professional photographer, my most recent job generated 24Gb of RAW images, double that amount once they're edited and that's 50Gb per job, and that fills up drives fast!).
2) I'll of course need a second 500Gb disk to mirror that first one.
3 & 4) two drives striped, for scratch. The largest Photoshop files I tend to work with hover around 1Gb, and I often use up to 5 layers for big files like this. I have 3Gb RAM on this machine (more RAM is my next planned upgrade, but after I get a Mac Pro), and so I depend quite a bit on scratch. I'm thinking of keeping costs down and using two smaller disks for scratch.
5) the 5th disk would be for archiving work. Once a project is complete and sent off to the client, I no longer need that data on my working disk. I plan to manually copy projects from the working disk to this "archive" disk. Once the archive disk is full, I'd pull it out of the enclosure and replace it with another one. I'm thinking one of the new 750Gb drives for this one.
I already have two FW800 500Gb disks on my desktop. I plan to retire them from active duty, and pull them out of the cupboard when I need to transport or shift data (like I think I will need to when I move from this G5 to a Mac Pro). I'd continue to use them, but they're going to be outclassed by the throughput of the eSATA drives, and I still have to offload the 1TB of data they hold to make them useful.
(BTW, you have to be equally careful when you reinstall OS X.)
One more question: what is your backup strategy?
Yeah, backup strategy. I remember having one...I used to run a DDS2 tape drive, but it couldn't keep up (I finally abandoned it when I moved from my SCSI-equipped G4 to this G5).
The main working disk will have a mirror, so I feel reasonable safe at not losing current data. I don't mind losing the scratch disks, and the archive disks (as they stack up in a cupboard) are of low priority (I'll probably wipe and reuse them after a suitable period of time).
I'll probably use one of the two soon-to-be-redundant FW800 disks to run Retrospect to (prob both). I won't be taking them off site (yeah, I know), but it's better than nothing.
When I'm a famous "one name only" photographer, I'll be able to afford everything I need (of course, that'll be when each photo will be 50Gb and I'll be sourcing petabyte drives).
So, do you think that I could do everything I want with 5-bay version of the following product? It seems like it has the best build quality of the various 5 bay port-multiplier solutions out there (the 5 bay version is about 1/2 way down the page):
MacGurus:Burly Port Multiplier SATA Enclosures
Can you recommend a card to go with a 5-bay PM enclosure like this one? (seems like this is a new product on the Mac side, are the bugs worked out?)
I'm obviously no expert in the RAID field, but I'm a mean photoshop user and a no slouch as photographer. If you ever have questions on those fronts, contact me any time! (I'd like to give back a bit :-)
[QUOTE=chasg]So, do you think that I could do everything I want with 5-bay version of the following product? It seems like it has the best build quality of the various 5 bay port-multiplier solutions out there (the 5 bay version is about 1/2 way down the page):/QUOTE]
Sure, if you want to go for a software RAID, yes.
Can you do us (= the community) a favor and write up your experiences? Another user in a similar position opted for a WiebeTech RT5. I would just like to juxtapose several RAID setups from an end-user's perspective :)
[QUOTE=chasg]Can you recommend a card to go with a 5-bay PM enclosure like this one? (seems like this is a new product on the Mac side, are the bugs worked out?)/QUOTE]
I have no personal experience with these adapters, but Wiebetech offers a card particularly for their 5-bay model.
Yeah, there is a reason that tape systems are geared for enterprise: deep pockets! (hmm, maybe I'll get into designing and manufacturing tape systems ;-)
Sorry about your data loss. I once lost 60gigs off a drive by accidentally trashing a directory on a network mounted drive while logged in on another machine ('cause it deleted the files immediately, rather than leaving it in the Trash, as I'm sure you know). Very bad news, as I didn't even notice the data was gone for a week or so :-/
Just to be clear: disk 5 is for archiving (these will be unique copies). I'm basically replacing burning to zillions of DVDs with archiving to hard drives. As projects are finished, they'll be totally moved off the working drive (drive 1) and on to drive 5 (and when it's full, I'll pull it, shelve it, and put in a new one). So, for incremental backups, I'll use the two available FW800 drives (which I'll probably wipe every month or so).
Thanks for setting my mind at ease with respect to the MacGurus product. I've written them and told them my requirements, we'll see how much it costs to get it over here to the UK :-/
When I get things up and going, I'll be happy to write out the whole story. It'll be nice to provide info rather than ask for it, for once.
Any time on the photoshop/camera queries!
Thanks again for all the help,
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