The answers to the pain involved in moving from Disksuite to Veritas
Volume Manager said either that there is no easy way or it is not too
hard. Draw your own comclusions from the responses, attached below.
Thank you very much for taking the time to respond!
Steven Sakata
Rick von Richter
Dave Burwell
David Thorburn-Gundlach
Robert L. Bailey
janet Hoo
Chris Woods
j. holland
Kevin Sheehan
Marco Greene
Roop Kumar
Original question:
If we were to choose Solstice Disksuite rather than Veritas Volume
Manager, and then Sun discontinued support for the former after we
already had it installed and working for a while, how painful is it to
convert to the latter? Experiences?
Thanks!
========================
Responses:
----------
I've worked with both packages, and I believe they are completely
incompatible. I would think you would have to back the Disksuite file
systems up, set up the Volume Manager file systems, and then restore.
----------
This direction is the easy one. i.e. going from SDS to VVM is an easy
(easier?) conversion than going from VVM to SDS. SDS uses actual slices
on the disk, so to "unconfigure" it only requires that you break any
mirrors, stripes, etc... and then modify your /etc/vfstab file to use
the /dev/dsk/cxtxdxsx devices instead of the /dev/md/dsk/dx devices.
Once you do that, you can then let VVM take over and go from there.
----------
According to Sun, they are not discontinuing DiskSuite.
If you wanted to convert from Disksuite to Veritas, or visa-versa,
FGI.
Major Pain (MP) and Heartbreak.
Back it all up, destroy the original disk set SW, and recreate using
whatever new Disk Management SW you like. Been there, done that
(DiskSuite
to Veritas).
----------
It's not too painful to convert; you just have to adjust your way of
thinking because the presentation of the two is pretty different. You
can even have ODS metadevices and Veritas LVs on the same system,
though it can be tricky to remember what disks belong to what grouping
of what manager :-) [BTW, you can also run VxFS on an ODS device,
just like you can on a simple disk; many folks think you have to have
VxVM to support VxFS, and it isn't true.]
If Sun ever really pulls support for ODS, we'll probably make
system-by-system conversions so that we don't have hetergeneous
systems as above, but we're using both in house and are familiar with
both.
Although VxFS (the Veritas journalled, extent-based filesystem) is a
whale of a lot better than UFS, it costs money; a nice step down from
that is logged UFS, which is supported by ODS (but not by VxVM -- guess
why :-) and is free. In addition, we stripe and mirror for best
performance and redundancy here at Pfizer, and ODS actually performs
better (1+0, which means to mirror up each disk and then stripe all of
the mirrors together -- so you can lose disks on both "sides" of the
mirrors without losing your whole stripe as long as those disks aren't
paired together) than VxVM (0+1, which means to stripe all of the disks
together and then mirror the stripe on more disks -- so if you lose a
single disk [even not paired together] on each "side" of the mirror
then you're screwed).
----------
Use Solstice Disksuite over Volume Manager?
Maybe I missed some other comments, but If I were you
I'd stay with VERITAS. Their disk management is far
better, IMHO, and more stable during disaster recovery.
----------
Backup and Restore. To my knowledge Sun is now working on a new version
of
Disksuite. I have asked around and to my knowledge no one has any
information
about support or the product being dropped. It seems to have been a
rumor that
got started when we OEM'd Veritas.
[This was from a person working for Sun]
----------
To my knowledge, there is no "easy way" to convert volumes created
with ODS to Veritas... I imagine that one would need to either build
the Veritas volumes while the ODS ones were still mounted (to allow
a cpio of the data across) or try to dump the volumes to tape...
Anyway, IMHO, Veritas is a vastly superior product for flexibility and
ease of use...
----------
I my opinion, I would go with the Vertias Volume manager. It is a
better
product for doing RAID configurations, etc. This product comes with all
our SSA configurations under the name Enterprize Volume manager.
[This was from a Sun Systems Engineer]
----------
I think (though am not sure) that Veritas has an answer to that
question.
Simple solution is to back up to tape and re-work the disks.
Also, I prefer VxFS to UFS on speed alone...
----------
If you are using a SPARC Storage Array, you should already have a
copy
of the VERITAS Volume Manager. There is no additional licensing costs.
Solstice Disksuite, at least in the next few years, will be supported by
Sun. Sun just created a new development team dedicated to the
improvement
of Solstice Disksuite. Mind you if you have VERITAS Volume Manager it
very
easy to set up and better designed to handle the extra load of a storage
array. I would recommend going with the Volume Manager to start with.
In answer to your converting question, you would have to back everything
up
to tape, uninstall Disksuite, install Volume Manager, set up your
volumes,
mount them and restore from tape. The amount of PAIN you would endure,
depends on how much data and backup solution that you are using.
WARNING: Do not use RAID 5 unless you:
1) Are not planning to do much writting (75% performance hit on writing
to
disk) The performance hit is due to the parity calculations that RAID 5
must do. Reading is fine.
2) Unless you are using a storage array that can perform the RAID 5
calculations for you, therefore, a much lesser performance hit. The Sun
A3000 can do this. I don't think that the lower Storage Arrays do this.
Especially not the SSA100
----------
SDS and VxVm, though both does almost the same functionality. the
formats and data files are completely different. Hence you may have to
go through BRR (Backup -Reload-Restore) cycle. VxVm is pretty much
similar in concept to SDS, but all the commands are totally diffrent.
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