Online file system replication over WAN

[Pradeep_3]

We have HP-UX 11i with Logical Volume Manager.
Can any one suggest replication software which would replicate file system data to other system over wan?

Thanks in advance
Fenil/Paresh

[Stefan Schulz]

Hi,

have you had a look on rdist - remote file distribution program?

This is a small tool you allready have. It should help you to start with.

Hope this helps

Regards Stefan

[Duncan Edmonstone]

It depends on whether you want the file systems to always be in sync (like for a database DR solution)- if so move to Veritas Volume Manager and use Veritas Volume Replicator.

http://www.veritas.com/products/category/ProductDetail.jhtml?productId=volumereplicator

If the file systems are relatively static and you just want to sync them up once a day/hour etc. you might want to look at rsync:

http://hpux.cs.utah.edu/hppd/hpux/Networking/Admin/rsync-2.5.5/

There are plenty of hardware based replication solutions out there to...but they generally cost a lot more

HTH

Duncan

[Lior Mishkovsky]

Hi,

There are numerous solutions,
You can check the following: 1. www.veritas.com site - few solutions.
2. www.xosoft.com - few solutions
3. HP has a solution call DRM - data replication manager, I'm not familiar with it - but it looks nice (using Nishan technology).

Lior./

[Jarle Bjorgeengen]

If you have a fibre-channel link, you can use LVM mirroring as well.

You anyway need a fast link if you want to keep in sync always, with data inconsitencies.

If only syncing at specific intervals , rsync is brilliant. It syncs on block-level, so if you have large files , it will sync only the necessary changed blocks, not the whole file.

Rgds Jarl

[Rita C Workman]

HP using Continuace Access
EMC using SRDF

These two are probably the best...and most expensive.

There is also the Veritas solution. Not my personal preference.

The next question might be are you looking to simply copy/mirror data....or be able to recover your systems. If you are leaning to systems recovery, then the first two are equally equal to that task.

Rgrds,
Rita

[Pradeep_3]

Thanks for all who replied, but EMC SRDF is very costly product.
Using VVR is also not possible as we are using Logical Volume Manager and to Veritas Volume Replicator can work only on Veritas Volume Manager.

Are there any other solution?

Paresh/Fenil

[Duncan Edmonstone]

Paresh,

If your determined to stick with LVM you are limiting your options - here's the complete stack with all the options I can think of:

- Application Layer - what application are you running on these file systems? Does it offer replication capabilities itself - most modern databases offer replication technologies via log or block shipping.

- File system layer - as your on HPUX the only file systems are VxFS and HFS - neither have replication options that I am aware of.

- Volume Management layer - LVMs only data replication capabilities are using mirroring - now you *could* join your storage devices at both ends of your WAN using some type of storage router to carry Fibre channel over IP, but this just isn't going to perform over a wide area link for mirrordisk where every read request and write request are sent to both storage devices. Obviously with VxVM you can use VVR, but you have already discounted that.

- Storage interconnect layer (SAN) - there are various devices available which will allow you to do replication between disks arrays within the storage interconnect - these generally assume that your interconnect is in reality a fibre channel based SAN - there are are a selection of products available which provide this kind of functionality (as well as lots of other functions) - they can be broadly be split into 'in-band' (such as HP's CASA http://www.hp.com/products1/storage/products/virtualization_appliances/network/sv3000/index.html or or DataCore's SANSymphony http://www.datacore.com/products/prod_home.asp) and 'out-of-band' solutions (such as Store-Age SVM http://www.store-age.com/storeage_web/index.html). Some of the new generation of SAN FC switches will have this kind of capability soon(not yet though)

- Storage device - the options depend largely on what storage device you have - all the major disk arrays support synchronous and asynchronous data replication, and they all cost a lot! (not least beacuse you usually need a v. expensive disk array at both ends)

I still think your best option is to go with VxVM and VVR.

Hope this is usefull

Duncan