TDP VMware vs. Cohesity


ADSM.ORG Senior Member
Aug 26, 2004
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Budapest, HUNGARY
Has anyone had experience with Cohesity?
  • Is it better than TDP VMware or Spectrum Protect Plus?
  • Is this the new direction?
  • Is it worth starting to get familiar with it?
At the moment IBM pushes OEMed Cohesity as preferred solution for VM backups.
I've seen it, but not used yet. It should be better than others:

ISPP is dead.
TDP for VE is alive, but I see no new features - looks like it is on support only, no plans for significant enhancement. I prefer it for small installations.
Cohesity starts with four hardware nodes cluster, which is big for smaller environments.
Cohesity is also available as fully configurable OVA file. You can use your own storage, but still use the advantages of a Cohesity cluster.
We used SP+ and switched to Cohesity a few years ago. It's one of the simplest products in the market with a very intuitive management interface. Teaming with Cohesity is the best decision IBM has made in years, although I'm afraid it should have been done years ago, instead of buying the product which they turned into SP+.

Kind regards,
Eric van Loon
Air France/KLM
Interesting. We're currently on SP+, and used Veeam before; but we are halfway in the market for another solution because, honestly, it's always something with SP+.

@EricVanLoon, does cohesity support offload to tape for long-term retention? We were promised that with SP+, and while it technically does so, the reality is that it uses an S3 interface to TSM which cuts the images in thousands of smaller blocks and takes ages to offload. Ideally I'd like direct-to-tape offload using a storage agent straight from the backup server... but I've begun to accept that very few products have actually considered such cases.
Actually, Cohesity (IBM OEM version) does it same way - over S3 interface to ISP/TSM.
Asked on a technical even recently - no known plans to make it offload data directly to tape.
Yes it does. "Cohesity simplifies long-term data and archival with a single, cloud-native solution that supports the backup and archival of data directly to leading public clouds including Amazon Web Services, Microsoft Azure, and Google Cloud or to tape" source:
"With Cohesity, IT organizations gain flexibility with support to archive data to multiple targetsthrough the same UI—public clouds, private clouds, any S3 compatible device, and QStar managedtape libraries."

It means over S3 interface, either to Qstar or IBM ISP / TSM. As I am aware, no option for direct attached tape library. Still, I may be wrong.
I checked with Cohesity itself and you're right, they only offer tape through QstarTape or through a SP server. Also no plans on the roadmap to make it available. For airgapped backups, Cohesity focuses on their owns SaaS based Fort Knox cloud solution.
Alright, thank you. Can't be worse than it is with SP+, I suppose :p

I'm not a fan of virtual airgapping, myself. I've been too long in this business to believe software solutions can be made infallible.
I wasn't very enthusiastic about SP+ too in the past. I know it has evolved since, but I think it will never be as intuitive as Cohesity.
If you want to have a look and feel experience with the user interface: they are offering a free 30 day trail through their website.
TDP for VE is alive, but I see no new features - looks like it is on support only, no plans for significant enhancement. I prefer it for small installations.
Cohesity starts with four hardware nodes cluster, which is big for smaller environments.

I would like to come back to this - what do you consider small? We've got around 800-900 VMs in backup; for a total of ~120T daily differentials on disk for 14 days. It's not peanuts, but it's not exactly humongous, either.

I have no experience with TDP for VE, but I assume like any native TSM solution it's going to dump stuff in a disk pool and then migrate it to tape; and I'd rather have restores consistently at tape speed than the five-minutes-or-five hours I get from SP+ depending on the position of the moon and the colour of my underpants.
Well, by small I was thinking smaller than that, maybe up to half of your env. It is big enough to consider Cohesity as better option, if there is enough resources available (money)

Still, it may be handled well by TDP for VE, if you are going to leverage some existing IBM licenses, or to upgrade a little upon them.
What is more important, if you go this way (TDP for VE)
Tape is not your friend.
You do not want operational VM backups residing on tape.
Tape may be used for another (air gap) copy, not for regular backup / restore jobs.
The thing is, unlike SP+, TDP for VE does not backup VMs as complete images, at once. It cuts them in so called mega-blocks, pieces of (if I am not wrong) 128MB each.
With incremental backups you will have your VM images scattered on many tapes, so no tape streaming from there, but countless mounting, rewinding and so on.
Even worse, beside "mega-blocks", there is also a tiny pointer file for every one of them, which you need to keep on disk all the time, since if it goes to tape - your restores will last forever.
For VM backups, on TSM server side, you go with container pool, on disks. These are pools which do dedup / compress, and they do it quite efficiently, for VM backups you may expect up to 80% savings, or let say your ~120T will probably fit to ~30T of disk, or a little more.

You should probably go with Cohesity, either directly or through IBM (they OEM it).
If there are existing IBM licenses that may be repurposed from SP+, and there are financial constrains, you may create proper solution with TDP for VE + ISP / TSM, but do not rely on tapes for operational backups.
Aha, that's very informative, thank you!

We do keep 14 days on disk as well, for pretty much the same reasons - you can't do a streaming restore (ie, create an temporary datastore on esx to instaboot the vm and then vmotion it) from tape/S3.

However, the cutting in blocks is basically my issue with SP+ as well (although I believe they're smaller still), and that is a misery to get back indeed.

We wouldn't be gaining much from dedup and compress - that 120T is the backup storage, not the VM store usage; and SP+ uses not just CBT on the VM side but also ZFS copy-on-write snapshots, so it's automatically deduplicated at the block level. I have opinions on how SP+ does all that, but we all know how fast RFEs get resolved at IBM :p

So it sounds like TDPVE's main benefit for us would be that it is fully integrated in our already extensive TSM environment, but we've got fairly good pricing for SP+ so that doesn't sound like an enticing migration.

I'll have a deeper look into Cohesity; but one of the nice things about SP+ (yes there are some :p) is that it basically runs in it's entirety on infrastructure we already have. The solution itself is all virtual; primary and secundary storage is on existing disk clusters (both unrelated to the vm storage, duh) and then it pushes to two tape libraries where it's also just a drop in the bucket. Maybe I just need to roll my own ZFS-to-tape solution :p
I haven't been using SPP (or SP+) much, but I find it OK, more or less. The biggest issue I noticed is that integration with ISP/TSM, and to tape, over it.

They even started making some effort on it, instead of using TSM as copy destination over S3 agent they introduced direct access, over OSSM

Then, someone ignited flamethrower at IBM, and SP+ is (unofficially) burned - you can't buy it any more. For support, not sure how long they are going to maintain it.
For the Cohesity (IBM OEM version) - operation wise, it looks a bit like SP+. TDP for VE is completely different concept.
As EricVanLoon wrote before, you may get Cohesity as completely virtual platform as well, like SP+, and use your storage, your infrastructure, but as I understood, preferred option is to buy hardware from them.
Let us know once you decide where are you going to, if choose to replace SP+.