Just a quick question on when to use VXFS vx UFS with logging.

Currently I have several 1 TB file systems (hardware RAID 5) using VXFS
with 8k extent sizes. One of our file systems has 8 million plus files
of varying sizes. This file system houses user home directories so
there are many small files as well as large files.

Lately, our backups started failing in this file system due to extreme
kernel contention. Veritas claims our kernel parameters and VXFS config
is good to go. I am currently moving this data to another 1TB file
system using UFS with logging but the data is moving at a painfully slow
rate.

Just wanted to get some feedback on UFS with logging, this is the first
I have ever used UFS with logging.

I am running Solaris 8 64-bit on this particular machine. (with latest
patch cluster as of last week)

Thanks for any advice,
Chuck

On Fri, 7 Nov 2003, Chuck wrote:

> Just wanted to get some feedback on UFS with logging, this is the first
> I have ever used UFS with logging.

UFS logging is great - especially in the latest releases of
Solaris 9, where performance got a significant boost.

How it compares to VxFS I can't say, as I've never compered
them.

HTH,

--
Rich Teer, SCNA, SCSA

President,
Rite Online Inc.

Voice: +1 (250) 979-1638
URL: http://www.rite-online.net

Rich Teer wrote:
> On Fri, 7 Nov 2003, Chuck wrote:
>
>
>>Just wanted to get some feedback on UFS with logging, this is the first
>>I have ever used UFS with logging.
>
>
> UFS logging is great - especially in the latest releases of
> Solaris 9, where performance got a significant boost.
>
> How it compares to VxFS I can't say, as I've never compered
> them.
>
> HTH,
>

"Compered" them - like in a quiz show?... VxFS, you *are* the Weakest
Link, Goodbye! ;^)

Chuck wrote:

>
> Just a quick question on when to use VXFS vx UFS with logging.
>
> Currently I have several 1 TB file systems (hardware RAID 5) using VXFS
> with 8k extent sizes. One of our file systems has 8 million plus files
> of varying sizes. This file system houses user home directories so
> there are many small files as well as large files.
>
> Lately, our backups started failing in this file system due to extreme
> kernel contention. Veritas claims our kernel parameters and VXFS config
> is good to go. I am currently moving this data to another 1TB file
> system using UFS with logging but the data is moving at a painfully slow
> rate.
>
> Just wanted to get some feedback on UFS with logging, this is the first
> I have ever used UFS with logging.
>
> I am running Solaris 8 64-bit on this particular machine. (with latest
> patch cluster as of last week)
>
> Thanks for any advice,
> Chuck
>


I'm not sure that in this case the underlying filesystem would affect
the transfer rate between two pieces of storage or the backup time.

The reason it's taking so long to backup (or not backup) is because of
the number of files. If you split the same filesystem in to two half
size filesystems and backed them up separately you would avoid backing
up the large number of files in one operation.

Elias

Chuck <usenet@zulu420.com> writes:

>I am running Solaris 8 64-bit on this particular machine. (with latest
>patch cluster as of last week)

Solaris 9 (later revs) ufs logging is *much* better, espcially for
your current workload.

What you could do for Solaris 8 with your current move is:

- suspend the transfer
- flush the log (lockfs -f )
- disable logging
- enable async ufs (look for the fastfs program)

Async ufs is unsafe but perfect for restores because it is
*much* faster. (Solaris 9 ufs logging is very similar in performance
to async fs)

Casper

Elias <nospam@charter.net> wrote in message news:<vqogc75g0c4jed@corp.supernews.com>...
> Chuck wrote:
>
> >
> >
> > [ ... ] Lately, our backups started failing in this file system due to extreme
> > kernel contention. [ ... ]

What is kernel contention?
>
>
> I'm not sure that in this case the underlying filesystem would affect
> the transfer rate between two pieces of storage or the backup time.
>
> The reason it's taking so long to backup (or not backup) is because of
> the number of files. If you split the same filesystem in to two half
> size filesystems and backed them up separately you would avoid backing
> up the large number of files in one operation.
>
> Elias


I agree that this sounds like a common problem with backups of a file system
with a large number of files. Moving from VXFS to UFS probably wont help much.

Some commercial backups products let you backup the raw device
and still restore individual files. Veritas calls this flashbackup, Legato's
product is called SnapImage.

dave dickerson wrote:
> Elias <nospam@charter.net> wrote in message news:<vqogc75g0c4jed@corp.supernews.com>...
>
>>Chuck wrote:
>>
>>
>>>
>>>[ ... ] Lately, our backups started failing in this file system due to extreme
>>>kernel contention. [ ... ]
>
>
> What is kernel contention?

Extreme mutex contention (spins on mutexes per second) I am currently
bringing up duplicate copies of 2 of our heavy usage 1TB filesystems
that are currently vxfs (ver 3.5 MP2).

I am gonna smoke test both and determine which one is best suited for.
(vxfs vs. ufs with logging) Sucks when you shell out the money for
Veritas and it doesn't perform as advertised, and then shell out even
more outrageous quantities of money for Veritas support that has yet to
proove it's worth to me in my 6 years exp. with Veritas.

-CC

>
>>
>>I'm not sure that in this case the underlying filesystem would affect
>>the transfer rate between two pieces of storage or the backup time.
>>
>>The reason it's taking so long to backup (or not backup) is because of
>>the number of files. If you split the same filesystem in to two half
>>size filesystems and backed them up separately you would avoid backing
>>up the large number of files in one operation.
>>
>>Elias
>
>
>
> I agree that this sounds like a common problem with backups of a file system
> with a large number of files. Moving from VXFS to UFS probably wont help much.
>
> Some commercial backups products let you backup the raw device
> and still restore individual files. Veritas calls this flashbackup, Legato's
> product is called SnapImage.

In article <3FB790DC.8030109@zulu420.com>,
Chuck <usenet@zulu420.com> did thusly spew forth:
>I am gonna smoke test both and determine which one is best suited for.
>(vxfs vs. ufs with logging) Sucks when you shell out the money for
>Veritas and it doesn't perform as advertised, and then shell out even
>more outrageous quantities of money for Veritas support that has yet to
>proove it's worth to me in my 6 years exp. with Veritas.

I fail to see the worth of VxFS if you've limited your atomicity to 8K
extents. The whole value of VxFS is with -variable- extent sizing. In
particular, VxFS doesn't begin to shine until you start using extents
-larger- than 8K. Smaller than that, performance will tend to still
favor UFS, as UFS doesn't start to incur indirection penalties until
about the 8K mark.

Basically, for home directories, unless your users are storing lots of
things like MP3's or similar large files, UFS probably would be a better
choice.

As to your backups, you might want to look at software that allows you
to do multi-streaming (several backup sessions from one block device or
filesystem).

-tom