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    NetBackup releases first disk-only backup features PDF Print E-mail
    Written by W. Curtis Preston   
    Friday, 13 June 2008
    With the release of NetBackup 6.5.2, Symantec has created a new watershed event: they have released (to my knowledge) the first mainstream backup features that require disk to use them.  Click Read More to learn more.

    NetBackup released Puredisk a while ago, and that was obviously a disk-only backup product.  But that is a product designed for the remote office, so I'm not putting it in the "mainstream" category.

    With 6.5.2 (released a few days ago), and 6.5.3 (due soon), they have released features for Sharepoint and Exchange that require disk.  Specifically, they finally have the ability to perform a single information store backup, and still do granular restore.  With Exchange, that means no more mailbox (AKA "brick level") backups in order to be able to restore mailboxes or messages.  They can (once 6.5.3 comes out) extrapolate mailboxes and messages from the information store backup, without having to do a separate backup.  The same is true of Sharepoint (in the current releas, 6.5.2).  They can perform a single backup of the entire Sharepoint server, while still being able to restore individual elements, such as documents.

    Both of these features are very welcome, but it's interesting that in order for them to work, the backups must be sent to a disk storage unit, or open storage (OST) storage unit.  Backing up to tape or VTL won't cut it.

    That's interesting, don't you think?  It's an important point in backup history, as far as I can see.  It sure is a sign of the times.

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    Rajesh   |2008-06-15 19:08:13
    Yeah. It is very interesting as well as frustrating for us. We used Disk STUs between 2003 and 2005 and with so many issues of disk stus those times (disks filling up and continuous 84 status codes etc), we switched to VTLs since with SATA drives on the VTLs cost of the operations came down. Now we have a lot of investment in VTLs and Symantec is focussing all their efforts in the disk storage unit area. Granted there are some additional things that can be done with disk stus, but many of the backup apps are designed to work well with tapes. And providing nice features like exchange and share point granular features to disk only customers is definitely not very welcoming.
    Tom Burrell   |2008-06-16 09:26:07
    To quote Steven Wright- You can't have everything... where would you put it? I sympathize that your VTL isn't supported with this, but at the same time it's no less useful now than it was yesterday. And with the declining cost of disk, it's not that cost-prohibitive to add some SATA disk as a DSSU/DSU to supplement your VTL where you can gain the benefits (ie: send just Exchange to a DSU for a short time -one week or so- to gain the granular restores, copy to VTL for longer term). We have found that sticking to one approach usually bites you- you need flexibility within your environment, and balance that with manageability.
    Rajesh   |2008-06-16 16:53:46
    Agreed. It is the time to rethink the whole thing. Need to check with the VTL vendors whether they allow a disk tray into the VTLs back end. It has its own complications, but certainly do able though.
    W. Curtis Preston  - Hold on!   |2008-06-17 01:34:09
    Let's not go abandoning the VTL world just yet. First, let's talk about Symantec, since they started this. All the VTL vendor has to do to work with these new features is to support the OST (open storage, uh, thing). It lets NBU talk to the VTL via an API that isn't tape. All the major vendors are either supporting it now or have plans to. If your VTL doesn't yet, put pressure on them to do it now.

    There are also other, more open projects out there to let VTLs interface with backup products, but they're too new to talk about I think.
    dirk dierickx   |2008-06-20 06:59:54
    what bugs me is that we you either have VTL or disk-stu (with nbu). but you can't have it in the same hardware.

    which is plain crazy, a lot of vtl are just known disk arrays with an appliance in front of it to present it as tape-drives but you lose all other connectivity options.

    why not just leave the possibility to divide the disk array in a percentage vtl and keep the other part available for regular san access, would make sense to me.

    i want to use vtl+dedup, but i _need_ to keep my disk-stu's as well, and i don't have money to buy 2 seperate disk arrays (1 regular + 1 vtl) for this...
    W. Curtis Preston  - Patience, grasshopper   |2008-06-20 10:06:56
    Because of dedupe, what you describe is not as easy as you describe. What you're asking for will come, but dedupe is definitely being given priority.
    dirk dierickx   |2008-06-26 03:00:18
    hp just released a new line of VLS, their top model is an EVA+dedup appliance on top of it, but it will also still allow regular access to the EVA for mounting filesystems and such.

    http://h18006.www1.hp.com/storage/disk_storage/disk_to_disk/vls/12000vls/index.html
    W. Curtis Preston  - That's good, but   |2008-06-28 15:39:15
    Don't expect that non-VTL disk to get deduped any time soon.
    James Lee   |2008-07-17 19:54:34
    Well, I was attending the Quantum DXI product launch. It is able to to have both VTL and NAS running in the same box, with data dedup across both VTL and NAS.

    Also, I remember seeing an Overland storage, which is also able to have both VTL and NAS options running in the same box, with dedup (not sure if it happens across both partitions tho).
    W. Curtis Preston  - That's not LUN access   |2008-07-18 10:27:36
    Don't confused NAS (filesystem access via IP) with LUN (block access via SCSI/FC).
    adrian aubrey   |2008-07-21 07:02:20
    Mr Preston said "Don't expect that non-VTL disk to get deduped any time soon"

    EVaults Infostage Backup Software uses purely disc to dics and non VTL too (any old discs will do) AND they de-duplicate that data at a BLOCK level as a background task - so that time is here ;-)
    That's across all O/S's and apps that they support not just Exchange and Sharepoint (EVaults sharepoint allows restores of portals, sites, sub site, indivdual documents and versions of documents - very granular)

    Adrian
    W. Curtis Preston  - You missed the point   |2008-07-21 10:18:41
    What you quoted me saying was "don't expect THAT non-VTL disk to get deduped any time soon." (emphasis added) I was referring to the non-VTL disk inside the VTL he was describing. What other vendors might do is not germane to that statement.

    As to what you mentioned, EVault falls into the category of source dedupe (dedupe that's done in backup software at the client/source). When we talk about NAS/VTL/LUN, we're talking about target dedupe (dedupe of regular backup data that's done in a target). You really can't compare the two. All of the source dedupe offerings back up to "regular" disk. It's the target dedupe offerings that aren't yet presenting a LUN to back up to.
    adrian aubrey   |2008-07-22 01:51:45
    Hi Mr Preston
    I'm sorry but you are wrong about EVault's capabilities. It does block level backups at the source (not de-duplication) and then the director software de-dupes the data at a block level as a background task on the standard discs that are used to store the data (target) - those discs can be DAS, NAS or SAN, SCSI, Fibre, SAS or SATA - pretty much anything you like really.
    I've not understood for a while why people would want to buy a separate VTL when there is software out there that will do everything a VTL will do, everything a data domain box will do but on a standard windows server with standard disc drives.
    I know that most people think of EVault as a low end service but they also have lots of customers who are running the software in-house and it works very, very well.

    Adrian
    W. Curtis Preston  - You need to read your own website   |2008-07-22 07:16:34
    I've been both a customer and a reseller for Evault (in a previous life), so I'd say that I'm more than familiar with your product. I'm not putting it down or saying that people shouldn't buy it, but you do seem to be saying that you don't know why people would buy anything else. Of course someone working for Evault would feel that way. (You DO work for them, right?)

    First, you are either misinformed or the evault site is wrong: http://www.evault.com/solutions/unified-recovery.html. It says "EVault InfoStage 6 includes the industry's most efficient data reduction and deduplication technologies."

    Second, even if all they do is use delta differentials (their historical approach prior to adding more global dedupe capabilities), most people would put that in the dedupe camp. (Two VTL dedupe vendors use delta differentials and they're called dedupe.) Funny, though. You don't seem to want to call it dedupe for some reason.

    Third, to answer your question, there are generally two reasons that people choose target dedupe over source dedupe. The first is familiarity/inertia and the second is speed.

    Familiarity/inertia: They know NBU/NW/TSM/CV/DP/BE/AS, or whatever they're using as they've been using it for years. They may like it, but they probably don't, but they at least understand it. It's easy to find someone with it on the resume, etc. Like it or lump it, it's what they have and what they know, and replacing it with a whole new product would be expensive and have a steep learning curve. It's easier for those customers to just patch or enhance what they already have and know by adding a deduped disk target than it is for them to replace it with evault/avamar/puredisk/asigra. Related to this is they may require functionality in their backup product not present in evault, such as SAP or DB2 backup, or the ability to archive to tape.

    Speed: I haven't tested Evault lately, but if it's like other source delta differential/dedupe products, it's not going to scale to the same speeds as traditional backup software. If I'm backing up a 5-150 TB Oracle database, I need to run that backup or restore at 100s of MB/s, if not over 1000 MB/s. Can Evault do that? I would be surprised if it did.

    What about a high-speed tape copy of the backup once the backup's done? Many companies still require a tape copy for a lot of reasons. Evault apparently doesn't have the capability. And if it did, it would probably not run at the speed we need it to run to keep up with modern tape drives.

    Source dedupe has its places: remote sites and medium enterprises. It has not been proven to scale in the large enterprise YET. (Show me benchmarks if you want to prove otherwise.) So until that time, we need traditional backup software and we need disk targets that can dedupe that software for us.

    Thanks for a lively debate. I always enjoy it.
    orb   |2008-07-22 09:18:36
    I'm surprised to hear that you know about the product, I've read a lot of your site and listened to a number of webcasts and have seen or heard little reference so assumed you either didn't like it or didn't know much about it - I stand corrected :-)
    You are very astute sir, I do indeed work for Seagate but in the UK but I am not suggesting for a minute that people wouldn't want to buy anything else - I'm not that naive as to think that our product fits all sizes - and again you are right in that we play in the remote and lower enterprise space and are only now starting to move up to larger organisations.
    On the de-dupe stuff - I think it depends on peoples definition of de-duplication. Our delta pro technology on the client end is just backing up the blocks that have changed which is not my understanding of de-dupication - so maybe the VTL vendors who are calling it de-dupe are jumping on that bandwagon because it's a hot topic. Our software does proper de-duplication during it's weekly optimisation process with the sole intent of reducing the amount of storage you require to store the backup and not to try and make the backup faster (we already do that by just backing up the blocks and by using the patented Quick File Scan to identify the changed files)- so maybe that explains why we don't call it de-dupe at the source.

    I perfectly understand what you are saying about inertia/familiarity - I worked for VERITAS for 4.5 years and met lots of people who hated BUE/NBU but who wouldn't change becuase they couldn't be bothered to learn something new and it's also very hard to go back to the board and try and explain why the $1m spend on NBU and a SL8500 library is now not what you need and you want to throw it away - it'll take some time yet before that happens wholesale.

    On the speed issue - I don't have a specific answer to your question but watch this space ;-)

    I do agree regarding high speed tape copy - our support for this is not very good but then we are selling to people who like us believe there is no need for tape. I would be interested to know why some people still "need" to use tape when a disc is cheaper, more reliable, reusable, doesn't need to be put on a van to move the data (which in itself injects a lot of potential hazards)- I have had the power objections to disc sitting there spinning but the likes of Nexsan are helping negate that one.

    Thanks also for the debate - I'm not questioning you as such just trying to gain more understanding of a subject that you obviously know a lot about.

    Cheers

    Adrian
    W. Curtis Preston  - I don't see it   |2008-07-22 13:47:06
    I don't talk about it much on the site because I don't see it in my customers, which is mainly the medium to large enterprise. I assumed that was because its capabilities and pricing were similar to those of other source dedupe backup products. (Both of which have tended to lend themselves to smaller companies.)

    I'll be happy to find out otherwise.
    Scott Sizelove   |2008-07-23 07:40:23
    DSU and VTL in the same dedup appliance = Data Domain. The Data Domain deduplicates all data as it comes into the system, this includes VTL via fiber channel, NAS via network, archive data from either, nearline data, replicated data, OST data, etc. Regardless of the media used to get it to the appliance it is compared to what it already has, no carving the disk for VTL only, NAS only, etc. The NAS piece can also be either NFS, CIFS, NDMP, or all at the same time.
    W. Curtis Preston  - Uuugh!   |2008-07-23 18:47:58
    NAS does not equal LUN. Yes, I know that DD & Quantum both provide both NAS & VTL access and that it's deduped. But neither of them (nor anyone else) yet provides a LUN that's deduped.

    (OK, actually one vendor does, as you can hand a LUN-based filesystem to Puredisk and have it dedupe anything sent to it, but the performance of that is similar to NAS, from what I've seen.)
    Joe Ropar  - NetApp = deduped LUN's?   |2008-07-25 14:25:36
    Curtis,
    I believe that NetApp can dedupe a LUN and pass back the savings through LUN thin provisioning.

    See paragraph 7.1 of:
    http://media.netapp.com/documents/tr-3428.pdf

    Regards,
    Joe
    W. Curtis Preston  - You got me!   |2008-07-25 14:28:28
    OK, two vendors do. ;) Has anyone tested the performance/dedupe ratio of NetApp's dedupe?
    Peter Elliman     |2008-09-04 19:37:25
    This has been fixed in NBU 6.5 with the feature called Advanced Disk (part of the Flexible Disk Option).

    You stage to a VTL and rolloff to a dedupe device. You can set different retention times on the image written to the VTL and to the dedupe device.

    And if you want to avoid buying two different disk arrays, you look into SharedDisk another new feature in NetBackup which might meet your needs.

    Finally, why do you want a VTL anyway (unless you have a lot of large NDMP backups).

    There is an excellent whitepaper on the new disk features here
    http://www.symantec.com/business/products/whitepapers.jsp?pcid=pcat_storage&pvid=2_1
    Peter Elliman     |2008-09-04 19:44:59
    Curtis - We should chat because your still thinking about our performance in terms of a VTL model. Because we dedupe at the media server level (proxy-dedupe), it really doesn't matter that we communicate from the NBU media server to PureDisk over ethernet because the data has already been deduped. So we don't need much bandwidth to send data to the PureDisk storage pool, especially after the first backup.

    Peter E
    W. Curtis Preston  - What was fixed?   |2008-09-04 20:31:35
    You're like 5 levels deep here in the comments, so I'm not even sure what you're replying to. Exactly what are you saying is fixed?

    Why are we many years into VTL deployments and I'm still explaining to people at Symantec why anyone would want one?
    W. Curtis Preston   |2008-09-04 20:33:38
    No I'm not, and I understand what you're saying. When comparing this to another dedupe device, though, the only thing that matters is how many MB/s of regular NBU backups can it handle. When I asked that question, I was told something like 100-200 MB/s. Those are NAS speeds.
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