![]() |
|
![]() | ||
|
Subject:
Dynamically expanding disk array
Category: Computers Asked by: johnmhome-ga List Price: $100.00 |
Posted:
28 Jul 2005 21:00 PDT
Expires: 27 Aug 2005 21:00 PDT Question ID: 549252 |
We need a small business storage system that can expand in capacity by adding more drives. We have used RAID5 type systems in the past, but they suffer the limitation that drives could not (5 years ago) be added to the cluster later to increase capacity, at least not without reformatting. We're thinking some kind of NAS box or SATA raid box or similar must surely support adding drives dynamically. Some downtime would be acceptable immediately after adding a drive, FYI. The target OS is windows, NTFS. We need reasonable data throughput, so 100Mbs ethernet might be OK, or fireware or even a PCI adapter. High speed SCSI is definitely not needed. Capacity we think should be around 600Mb starting, and expanding to 2TB. We don't need guaranteed uptime and other enterprise type features. The box is to be used in an important part of the business, but it's not colocated in the data center. Cost $1k to $5k seems reasonable. Recommendations for suitable products ? |
![]() | ||
|
There is no answer at this time. |
![]() | ||
|
Subject:
Re: Dynamically expanding disk array
From: dooley-ga on 29 Jul 2005 00:06 PDT |
http://h18004.www1.hp.com/products/servers/proliantstorage/sharedstorage/sacluster/index.html fits your spec and price |
Subject:
Re: Dynamically expanding disk array
From: captain_brainiac-ga on 30 Jul 2005 20:31 PDT |
You didn't mention if you needed a tower or rack configuration - but here's a rack mounted solution. Cost per MB is cheaper with SATA drives than with SCSI drives. I prefer SCSI (for performance reasons) in a business solution, but SATA should work just fine for what you're looking for. As to adding to an array once it's been created, SCSI RAID controllers will be more robust and focused on expandibility/configurability with minimum downtime. Regardless, for a rackmount enclosure, I would recommend something like this: http://www.techonweb.com/products/productdetail.aspx?id=B68275&src=FG $2,813 for an 8-bay SATA enclosure (connects to host machine via SCSI U16 - includes adapter) 6x$400 ($1,500) for 6 SATA drives (for RAID 5)= 2.0TB of storage Total Cost = $4,313 You could definitely go more expensive, but I'm not sure your needs require it. I would definitely fill the remaining two bays so that you can have global hotswaps available. If you're in GA and need hand-on help, let me know and I can provide specifics along with install services. |
Subject:
Re: Dynamically expanding disk array
From: johnmhome-ga on 31 Jul 2005 10:44 PDT |
As I said in my posting, high speed scsi is definitely not needed. SATA is ideal because of cost. I prefer to avoid SCSI to the host also, because of the infexibility of the cabling involved. Firewire is good enough. The most important thing is that we can add drives later and expand capacity without reformatting. I need to know precisely which solution offers this and how it works. |
Subject:
Re: Dynamically expanding disk array
From: captain_brainiac-ga on 31 Jul 2005 16:04 PDT |
Sorry for my math being off on the drives in the previous post (it had been a long day). The actual total should have been $5,213. Regardless, it sounds like you're looking for a consumer class device that will deliver enterprise class features (a tough bill to fill). There are many different ways you can go with this, but I don't think that the demand is such yet to warrant companies building 1394 RAID devices with 2TB RAID5 capacity. If you *are* able to find one, it may be by such an obscure manufacturer that it'll be almost impossible to support if something ever goes wrong with it. When you say that SCSI cabling is not flexible enough, can you be more specific? Are you talking about physically routing it from one device to the other? Or are you talking about terminating, SCSI ID's and such? Also, is this going to be rack or tower mounted? Finally, I really don't understand your final statement about having to reformat when you add drives. I've been doing this type of work for 15 years and the worst I've seen (when adding capacity only) is that you actually have to down the server for the changes to take effect (when you're expanding an array). However, most cards now days offer online capacity extension. If in doubt, just look through the specs for the controller card. If you could give me a little more information, I'd love to help you out. But as I said earlier, because of your storage requirements, you may need to step into an enterprise class product - even though you may not need/use all of the functionality. |
Subject:
Re: Dynamically expanding disk array
From: johnmhome-ga on 01 Aug 2005 19:11 PDT |
this is primarily for a desktop workstation application and I've always found that SCSI cabling is klunky. I imagine putting the box on the floor out of the way and also to cut the noise. Given that I want avoid rackmount, and also hotswap is not needed (per my original post, it's not a 24x7 uptime situation) www.micronet.com seems to have somewhat suitable devices. Opinions? Now, onto the critical question of capacity expansion. I understand the array can be expanded by adding drives, but does anything need to happen at the OS level? Does the RAID controller understand an NTFS disk and expand the partitions accordingly? |
Subject:
Re: Dynamically expanding disk array
From: captain_brainiac-ga on 01 Aug 2005 21:40 PDT |
I'll answer your questions backwards here... As to online capacity extension and partitions...No, a RAID array controller will not modify the partitions on the disk. It will either look like (through the OS) that partition/logical drive is sitting on a larger physical drive, or you'll have a whole new physical drive altogether (if you create a new array). If you want to expand your partitions without having to backup, resize, restore, you can always use PartionMagic (Symantec owns them now). **WORD OF WARNING** Make sure you have a good backup before using this program. It works and I highly recommend it, but if something goes awry (or you screw something up), very high potentional for losing data. As to the the site you recommended, the only firewire/1394 device I see have 5 bays. If you populate this drive out with 500GB drives, you can achieve 2TB RAID5. However, the site doesn't say whether or not 500GB drives are supported. Also, I don't understand where they say, "Up to 2.0TB raw storage capacity utilizing 300GB drives." With 5 bays at 300GB a pop, I believe that's only 1.5TB (1.2TB RAID5). Also, ordered in their 2.0TB configuration, you'll only receive 400GB drives which will put your raw storage at 2.0TB, but your realized storage w/ RAID5 at 1.6TB. It's late, maybe I'm reading something wrong, but their math seems off... |
Subject:
Re: Dynamically expanding disk array
From: captain_brainiac-ga on 01 Aug 2005 21:45 PDT |
Oh ya... SCSI cabling used to be pretty bad (maybe around 10 years ago). It's late I'm probably off a little on my terminology, but back then you were dealing with a 50-pin to centronics type connector for SCSI I. These cables were real thick and were kind of a pain. But the SCSI3 cables out now are a completely different story - they're much more flexible (and smaller in diameter). As to the noise of the device/enclosure, your interface type won't affect this. Going with 7.5K vs 10K drives will. Number of fans will. Number of drives will. Manufacturer of drives will. Construction of case will. Power saving capabilities will. Interface will not (they're silent to begin with - unless you can hear your IDE controller). |
Subject:
Re: Dynamically expanding disk array
From: aidanjt-ga on 06 Aug 2005 11:48 PDT |
Okay, I've spent some time reading through this question trying to fathom what you're trying to do with a workstation application that will need up to 2TB of storage.. surely something with that capacity of data would be better off with a database server managing the information? And if the application indeed requires a Windows workstation with raw access to files, then the performance hit will likely to be severe, you might want to look into alternitive methods of solving the same problem. More information on the actual problem might deliver a better solution. Just a suggestion. |
Subject:
Re: Dynamically expanding disk array
From: johnmhome-ga on 07 Aug 2005 14:06 PDT |
Our app *is* the database, effectively. Complicated to explain why we don't shove the data into a database, so suffice to say that we're the developer of the software and this query is helping us refine what storage hardware to recommend to our customers. Normally that would be easy, but they are SMBs with small budget and we need to dynamically expand the storage (thanks for the comments about partitions earlier. That confirms my suspitions). I'm thinking a cheap SAN box is the way to go. Forget SCSI/Fireware. If we have 100Mb ethernet (1G perhaps?) that's going to be quick enough for this app. So, is there a SAN box that offers RAID, is aimed at SMB, and can have volumes added on-the-fly. I'm thinking because it's SAN it could be expanded because the access if via SMB, which doesn't know about physical partitions. |
Subject:
Re: Dynamically expanding disk array
From: wengland-ga on 25 Aug 2005 09:54 PDT |
XSan from Apple will do it, but at a higher cost than you want to pay. http://www.apple.com/xsan/ I'd guess around $8K depending on your needs, but it can expand to around 2,000 Terabytes. Basically, you are looking for a Veritas File System for NTFS prices. |
Subject:
Re: Dynamically expanding disk array
From: johnmhome-ga on 29 Aug 2005 07:58 PDT |
Aha, so can you confirm there is no cheap device that I can resize later by adding more drives? The XSan looks good, but too pricey as you predict. Any others? |
Subject:
Re: Dynamically expanding disk array
From: mattix2005-ga on 30 Aug 2005 23:12 PDT |
supposedly this thing expired, but there's an easy way to do this, unless you need the actual filesystem to be local and NTFS. You can use a remote disk server to do this and use microsoft SMB filesharing over a highspeed network (gigabit or even faster, say infiniband for throughput) - tho really gigabit has a theoretical max of 120mb/s (actual range is 100mb/s). Infiniband is 10x faster (and alot more expensive but possibly worth it - your disks will be the bottleneck with infiniband unless you have a huge SAN.) The basic idea here is to setup a linux disk server running lvm2 or EVMS to allow expandable virtual volumes and filesystems with hotswap SATA bays on a multiport SATA card (3ware or LSI or otherwise), and use SAMBA networking to share the disk over the network. Disks can be added at whatever time, and here's the kicker, using MATURE filesystems in linux (say not ext3, the standard linux fs, but like XFS, which is SGI's extremely great and much better tested fs) you can expand the filesystem LIVE when you add disks. email me at mattix-answers-google at sizone.org about this if you want more details, and I can give you some more specific details on likely pricing and what not. |
If you feel that you have found inappropriate content, please let us know by emailing us at answers-support@google.com with the question ID listed above. Thank you. |
Search Google Answers for |
Google Home - Answers FAQ - Terms of Service - Privacy Policy |