recommendations for OSXS and RAID

[option8]

my current setup – OS X server 10.3 running on a dual G4 desktop with a couple of nice chunky drives (2 x 40 gigs) attached, being backed up via retrospect/SDLT – works fine for what it was originally intended, i.e. as a common shared drive, to transfer files from one machine to another, as cold storage for archiving project files before burning to CD/DVD, and repository for shared project files. all for our smallish design group.

now that the group has expanded considerably, and our storage and backup needs are threatening to outstrip capacity, i’m thinking of what to do next. specifically, of what to put in 2005’s budget.

my boss has decided (and i tend to agree) that we’re losing too much productivity with project files (layouts, scans, fonts, etc) sitting on one person’s computer, that frequently need to be accessed by others in the group. sorting duplicates and version control of documents has become an issue. my boss thinks that all this can be solved by everyone storing their files on the server. however, the server as it’s set up now doesn’t have the capacity for everyone to have their files on the server – thus, everyone has their own current files on their own hard drives, each getting backed up over the network at night. not exactly ideal, but, like the ungainly giraffe, a product of evolution.

so to my point – and i do have one. i like the distributed nature of our current storage “solution” for one reason – there is no single point of failure. if a user’s drive goes up in smoke, it’s a relatively simple matter to replace it and restore from the latest retrospect snapshot of that drive. with individual drives having anywhere from 5 to 30 gigs of active projects, and some with as much as 100 gigs of older stuff still on them, it’s a bit of a chore, but it’s something i’ve done before in a day. meanwhile, everyone else in the group can still happily chug away. if the server goes offline, it’s not a big deal, as its biggest duty is in backing up and archiving, so again, everyone can work as usual.

what i’m looking for is an informed recommendation from other people on this forum as to how best to proceed.
do i pull the existing small drives from the server and fill it with 250s in a mirrored software RAID (using the built-in OS X RAID via disk utility) – i see this as cheap and relatively secure: just the drives and maybe a SATA card to buy. but how good is OS X’s RAID for recovering a borked drive? i’ve never done it, myself…

option 2 would be to buy an XRAID or similar external hardware with the necessary controller and software to manage it. considerably more expensive, but more extensible for future growth. also more flexible in the way the RAID is set up (0, 1, 3, 5, 0+1, 30, 50…). but is the G4 up to the task of keeping the XRAID happy and the data churning?

option 3 would be to scrap the G4 entirely, and replace it with an XSERVE (ideally at some point after Tiger comes out, as it would come with another OSXS license) filled with 250 or 300G drives.

are there other options out there? my concern with something that’s not at least a mirrored RAID (such as the lacie Terabyte drive) would be that i’d have to find some way of backing it all up. our 120gig tapes are already filling up at an alarming rate, and there’s nothing out there short of a second terabyte drive to back things up…

[ghostman]

I know all too well the questions you’ve asked – I’ve dealt with them all.

First, if your client computers are or will be connecting to your server with AFP or SMB over IP, I would recommend getting an XServe or at least getting OS X Server software. The networking in Panther Server is optimized and you’ll get better file transfer speeds.

From experience, I would not recommend Apple’s mirroring to keep your data safe. Mirroring does not allow for failover – if one drive dies, the server unmounts both until you fix or replace the bad drive. And Apple’s fix is not very pretty if you are not UNIX savvy. To heal mirrored drives, you must type several intricate command lines and cross your fingers (my company track record is 1 success and 1 failure with this). It isn’t something for the faint of heart and definitely not something that an end user could do in an emergency.

If you are really trying to centralize storage, it must be robust and have fault tolerance. If it goes down and end users loose data, they will have no faith in the system and will continue to save their work locally.

I’ve have good success with RAID 5 solutions. Briefly, RAID 5 has a controller that watches the drives for faults and writes parity to the drives. You’d need a minimum of 3 drives online – two would be striped with data and the third would be a hot spare. If drive one or two fails, the controller rebuilds the data (based on the parity bits) to the third drive. You can hot swap the bad drive with a new drive at any time (the sooner the better just incase you have another bad drive).

The XServe Raid is a nice solution. But with one caveat – ATA drives. They don’t seem to be as robust at turning 24/7 and you might have to replace them more often than with SCSI or Fibre Channel drives. But they are much cheaper to replace (especially if you buy your own drives and just replace them in the Apple sled module).

You might want to look into eRaid. It is a stand alone RAID 5 box that supports FireWire 800.

[Helder Dias]

The downside I see on the eRaid solution is that it hasn’t ethernet or fibre channel that would ease the data access by all coworkers.It has only an external Sata connection and FireWire 400 and 800 and USB 2.0. The only way I see to use it was through FW 800, connecting them all by IP-over-FW ( and they must have FW 800 on the board or through pci cards ).

Now help me to analyse another scenario ( I don’t know if it’s the better so I ask you help ). If he as good dual Power Mac ( dual 800 or better ) he coul buy a High Point RocketRAID 1820 A serial ata Raid card ( which is being sold around US$200-250 ), that provides Raid 5 and 10 support and has 8 channels and with at least 3 250 GB/8 MB cache hard disks he could have a good amount of reliable and fast storage, all for less than $700.This configuration could be enough for 1 or 2 more years for their needs. And compare that to a dual Xserve with 1 GB of ram, raid card and 3 250 GB HD’s : $5,799.

If more storage is needed then he could use the eRaid connected to a Firmtek seritek 1se2 pci card.

Now, about data sharing: Gigabit Ethernet or a FibreChannel card connected to a Fibre switch and cards ( I know, I know… it would cost him both arms and legs! )? Which way to go?

If It was me I would do this I saw on xlr8yourmac ( http://www.xlr8yourmac.com/systems/SonofFrankenMac/son_of_frankenmac.html ) : place the board on a large case and 8 Western Digital 300 GB serial ata HD’s connected to the RocketRAID card ( Raid 10 ). Fasten your belts!

[Helder Dias]

Excuse me for some misspelling errors om my previous post.

[Helder Dias]

ghostman,

Sorry, I didn’t realized promptly the eRaid ( at least the one shown on fwdepot.com ) is a disk array, so of course it should work as a cheap and capable substitute to Apple’s XRaid, connected to the Power Mac either through FW 800 or Serial Ata.

Another way could be a cheap new or used disk array for 10k rpm SCSI drives.

[option8]

thanks for the insights guys. to respond to a previous post, i’m already using OSX Server on the G4, and it’s handling the load pretty well as is. the immediate problem is one of storage, not one of speed (if it were, i’d be replacing the 100 mbit network with something much faster, but this is the network i share with ~30 PC users, and they have their own server to worry about)

i’m working through my options now, and thought i’d ask another followup re: future expansion.

the way i see it, the best option in that regard is the Xserve RAID. 14 bays to add new drives to for more capacity, vs the Xserve’s 3 bays. if i fill an Xserve up with 3 250s and set it up with RAID5, that’s ~500 gigs of storage, max. if i wanted to replace the 250s with 400s, say, how would that go? i’d have to offload everything to something else that can handle 500g, install and format the 400s, then move it all back.

where do i get another 500g for the short term? if i had that, i wouldn’t need to upgrade the 250s in the first place… also, what do you do with 3 Xserve drive modules? hold onto them? ebay them? throw them into an Xserve RAID if/when i get one?

has anybody gone through the process of upgrading all 3 drives in an Xserve before that can share with the group?

[Helder Dias]

option8,

From what you say the current Powermac and the network are fast enough even considering the additional load caused by transforming the Powermac from a backup to a real file serving machine to your small design group ( 5 to 10 users? ), right?

Do you see, in the next year or so, a huge increase in work and projects, that justify buying a G5 XServe to replace the G4?

The XServe RAID is wonderful…and cheap, compared to proposals from others. But even then evaluate if your boss can afford it and the upgrade path of buying drives from Apple from time to time.

About software can someone tell us how good is Apple’s Xserve RAID Admin Tools? Other than SoftRAID ( RAID 0,1 and 3 ), are there other decent software solutions?

From what I see, and concluding, if your needs are not very demanding and money is a constraint, keep the G4, place one or two 8 MB cache SATA drives inside it and add an eRaid.

If you can convince your Boss, make no mistake, go for the XServe RAID, or even better, control it with an XServe G5. But honestly, IMHO, the G4/eRaid duo is sweeter, since for a fraction of the cost it may do 90-95% of what the XServe/XServe RAID can do for your needs, that seem to be not very demanding.

Please comment my thoughts.

[option8]

our workgroup is currently at about 15 users, two of them doing a lot of video and the rest doing print and web design, and i see that load increasing over the next 6-12 months. the video guys each have about 1.5 TB of storage attached to their machines for final cut and uncompressed video, so they’re not going to be using the server for their stuff, but it’s worth considering their needs into the future.

by my rough estimates (and some poking around with remote desktop reporting) i figure we have roughtly 485 gigs of data spread between the 15 desktops and the server now. much of that is system overhead (apps, library, fonts, etc) and not project files that need to live on the server, but still, it’s a lot more than the G4 can handle as-is. even by adding the SATA software RAID to the G4, it would probably be immediately filled up, or be at capacity shortly thereafter.

i’m leaning towards an xserve, especially considering the availability of 400 gig modules for it now. three of those in RAID3 gives me ~800 gigs to play with, which should be enough to grow on for a while. this leaves the G4 i have for doing archiving and backups. in a year or three, if we’ve outgrown the xserve, we can add another, or an xserve RAID to the mix.

while this is a ~$5,000 solution, i think it’s a good compromise, considering the potential for expansion.

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