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Afternoon,
I don't have the kit to test this, but I would expect the CPU hit to be
pretty similar for VTL and DSU/DSSU. They're both simply writing data to a
SCSI device, but the DSU/DSSU will have whatever overhead a filesystem
puts on your system which I would expect to be pretty small where it is
sequential writes of large files (not sure but using directio mount option
may improve DSU performance where available like on Solaris). The number
of concurrent jobs is really going to be down to your hardware specs, ie
how many disk spindles are u writing to, how many HBA's are you writing
via, and do u have enough CPU power and internal bus bandwidth to IO
saturate the backup devices,
cheers Andy.
Kathryn Hemness <kfhemness AT ucdavis DOT edu>
Sent by: veritas-bu-admin AT mailman.eng.auburn DOT edu
23/03/2006 16:52
To: veritas-bu AT mailman.eng.auburn DOT edu
cc:
Subject: [Veritas-bu] RE: on the subject of disk based
backups....
Good Morning --
I'm curious about the CPU hit and overall throughput of VTL vs
DSU or DSSU backups. How many concurrent backups can run
from a single server? The most I can run on my servers with DSUs
is 10 per server.
--kathy
> To: "Paul Keating" <pkeating AT bank-banque-canada DOT ca>
> Cc: veritas-bu AT mailman.eng.auburn DOT edu
> Subject: RE: [Veritas-bu] on the subject of disk based backups....
> From: andrew.x.smith AT jpmchase DOT com
> Date: Thu, 23 Mar 2006 15:59:33 +0000
>
> This is a multipart message in MIME format.
> --=_alternative 0057D9418025713A_=
> Content-Type: text/plain; charset="us-ascii"
>
> Yeah, for me the biggest weakness of the NBU DSSUs.
>
>
>
>
>
> "Paul Keating" <pkeating AT bank-banque-canada DOT ca>
> 23/03/2006 15:48
>
>
> To: <andrew.x.smith AT jpmchase DOT com>
> cc: <veritas-bu AT mailman.eng.auburn DOT edu>
> Subject: RE: [Veritas-bu] on the subject of disk based
backups....
>
>
> excellent info...Now that you mention it....my one small DSSU I have
> configured to offload to a specific tape pool, so I should have known
> that.
> That definately sways me in the direction of VTL then.
> -----Original Message-----
> From: andrew.x.smith AT jpmchase DOT com [mailto:andrew.x.smith AT jpmchase
> DOT com]
> Sent: March 23, 2006 8:30 AM
> To: Paul Keating
> Cc: veritas-bu AT mailman.eng.auburn DOT edu
> Subject: Re: [Veritas-bu] on the subject of disk based backups....
>
>
> Hi Paul,
>
> from my experience what you say about DSSU is incorrect, a single DSSU
> cannot stage the data off to multiple tape tape pools - if you have a
> requirement to stage to different tape pools you need to have a at least
> one DSSU per tape pool,
>
> cheers Andy.
>
>
>
>
>
> "Paul Keating" <pkeating AT bank-banque-canada DOT ca>
> Sent by: veritas-bu-admin AT mailman.eng.auburn DOT edu
> 23/03/2006 13:05
>
> To: <veritas-bu AT mailman.eng.auburn DOT edu>
> cc:
> Subject: [Veritas-bu] on the subject of disk based
> backups....
>
>
>
> I'm also interested in thoughts regarding VTL vs DSSU.
> DSSU interests me mostly because I can write multiple jobs at once
without
> any regard for tape pool, mpx or not, retention, etc.....
> ...then it all gets sorted out to appropriate tapes during the destaging
> VTL still presents itself to NBU as a tape, so each virtual tape drive
> must be licensed with Veritas, in additional to the physical tape drives
> (unless the VTL is run inline, though there could be issues there
> regarding estimated compression, etc.)
> Just a couple things off the top of my head.
> Just wondering who is using DSSU, adn who is using VTL, adn why you made
> that choice....ie.what were the key requirements for your environment
that
> made one option better than the other.
> Paul
>
>
_______________________________________________
Veritas-bu maillist - Veritas-bu AT mailman.eng.auburn DOT edu
http://mailman.eng.auburn.edu/mailman/listinfo/veritas-bu
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<br><font size=2 face="sans-serif">Afternoon,</font>
<br>
<br><font size=2 face="sans-serif"> I don't have the kit to test this,
but I would expect the CPU hit to be pretty similar for VTL and DSU/DSSU.
They're both simply writing data to a SCSI device, but the DSU/DSSU will have
whatever overhead a filesystem puts on your system which I would expect to be
pretty small where it is sequential writes of large files (not sure but using
directio mount option may improve DSU performance where available like on
Solaris). The number of concurrent jobs is really going to be down to your
hardware specs, ie how many disk spindles are u writing to, how many HBA's are
you writing via, and do u have enough CPU power and internal bus bandwidth to
IO saturate the backup devices,</font>
<br>
<br><font size=2 face="sans-serif">
cheers Andy.</font>
<br>
<br>
<br>
<br>
<br>
<table width=100%>
<tr valign=top>
<td>
<td><font size=1 face="sans-serif"><b>Kathryn Hemness <kfhemness AT ucdavis
DOT edu></b></font>
<br><font size=1 face="sans-serif">Sent by: veritas-bu-admin AT
mailman.eng.auburn DOT edu</font>
<p><font size=1 face="sans-serif">23/03/2006 16:52</font>
<br>
<td><font size=1 face="Arial"> </font>
<br><font size=1 face="sans-serif"> To:
veritas-bu AT mailman.eng.auburn DOT edu</font>
<br><font size=1 face="sans-serif"> cc:
</font>
<br><font size=1 face="sans-serif"> Subject:
[Veritas-bu] RE: on the subject of disk based
backups....</font></table>
<br>
<br>
<br><font size=2 face="Courier New">Good Morning --<br>
<br>
I'm curious about the CPU hit and overall throughput of VTL vs<br>
DSU or DSSU backups. How many concurrent backups can run<br>
from a single server? The most I can run on my servers with DSUs<br>
is 10 per server.<br>
<br>
--kathy<br>
<br>
> To: "Paul Keating" <pkeating AT bank-banque-canada DOT
ca><br>
> Cc: veritas-bu AT mailman.eng.auburn DOT edu<br>
> Subject: RE: [Veritas-bu] on the subject of disk based backups....<br>
> From: andrew.x.smith AT jpmchase DOT com<br>
> Date: Thu, 23 Mar 2006 15:59:33 +0000<br>
><br>
> This is a multipart message in MIME format.<br>
> --=_alternative 0057D9418025713A_=<br>
> Content-Type: text/plain; charset="us-ascii"<br>
><br>
> Yeah, for me the biggest weakness of the NBU DSSUs.<br>
><br>
><br>
><br>
><br>
><br>
> "Paul Keating" <pkeating AT bank-banque-canada DOT ca><br>
> 23/03/2006 15:48<br>
><br>
><br>
> To: <andrew.x.smith AT
jpmchase DOT com><br>
> cc: <veritas-bu AT
mailman.eng.auburn DOT edu><br>
> Subject: RE:
[Veritas-bu] on the subject of disk based backups....<br>
><br>
><br>
> excellent info...Now that you mention it....my one small DSSU I have<br>
> configured to offload to a specific tape pool, so I should have known<br>
> that.<br>
> That definately sways me in the direction of VTL then.<br>
> -----Original Message-----<br>
> From: andrew.x.smith AT jpmchase DOT com [mailto:andrew.x.smith AT
jpmchase DOT com]<br>
> Sent: March 23, 2006 8:30 AM<br>
> To: Paul Keating<br>
> Cc: veritas-bu AT mailman.eng.auburn DOT edu<br>
> Subject: Re: [Veritas-bu] on the subject of disk based backups....<br>
><br>
><br>
> Hi Paul,<br>
><br>
> from my experience what you say about DSSU is incorrect, a single
DSSU<br>
> cannot stage the data off to multiple tape tape pools - if you have a<br>
> requirement to stage to different tape pools you need to have a at
least<br>
> one DSSU per tape pool,<br>
><br>
> cheers Andy.<br>
><br>
><br>
><br>
><br>
><br>
> "Paul Keating" <pkeating AT bank-banque-canada DOT ca><br>
> Sent by: veritas-bu-admin AT mailman.eng.auburn DOT edu<br>
> 23/03/2006 13:05<br>
><br>
> To: <veritas-bu
AT mailman.eng.auburn DOT edu><br>
> cc:<br>
> Subject:
[Veritas-bu] on the subject of disk based<br>
> backups....<br>
><br>
><br>
><br>
> I'm also interested in thoughts regarding VTL vs DSSU.<br>
> DSSU interests me mostly because I can write multiple jobs at once
without<br>
> any regard for tape pool, mpx or not, retention, etc.....<br>
> ...then it all gets sorted out to appropriate tapes during the
destaging<br>
> VTL still presents itself to NBU as a tape, so each virtual tape drive<br>
> must be licensed with Veritas, in additional to the physical tape
drives<br>
> (unless the VTL is run inline, though there could be issues there<br>
> regarding estimated compression, etc.)<br>
> Just a couple things off the top of my head.<br>
> Just wondering who is using DSSU, adn who is using VTL, adn why you
made<br>
> that choice....ie.what were the key requirements for your environment
that<br>
> made one option better than the other.<br>
> Paul<br>
><br>
><br>
<br>
_______________________________________________<br>
Veritas-bu maillist - Veritas-bu AT mailman.eng.auburn DOT edu<br>
http://mailman.eng.auburn.edu/mailman/listinfo/veritas-bu<br>
</font>
<br>
<br>
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