What Tim really needs is a way to move data from the XP to the VA at fiber
speeds - but wait, isn't that supposed to be the promise of storage area
networks? It seems the biggest bottleneck is the HP3000. Is there a way to
move the bits without the HP3000 playing a role?

John


> -----Original Message-----
> From: HP-3000 Systems Discussion [mailto:[log in to unmask]]On
> Behalf Of Denys Beauchemin
> Sent: Monday, February 21, 2005 7:49 PM
> To: [log in to unmask]
> Subject: Re: [HP3000-L] Moving from XP512 to VA71xx
>
>
> Well, for one thing I believe the fiber channel supports
> 1Gb/second, This is
> one gigabit per second and you are talking about 500
> gigabytes of data.  I
> look at fiber channel as 100MB/second.  So even if the VA7100
> was going at
> full blast, it would take 5,000 seconds to transfer all the
> data, a little
> under one and one half hours.
>
> But the VA7100 does not transfer or receive at 100MB/second,
> it can, but the
> 3000 won't let it do it.  Now, since the VA7100 can blast out
> at 90MB/second
> (as an array, not from a single drive,) and the VA7110 has a
> maximum output
> of 160MB/second, I would venture to say that a sustained read
> or write from
> a VA7100 going through a 3000 as it does file copies, will
> probably max out
> at around 30-40MB/second.  Just a guess.  By the way, the
> rated write speed
> of the VA7100 is 45MB/second, and 84MB/second for the VA7110.
>
> So you say, but Denys, the write speed is about half of the
> read speed, so
> your restore should take twice as long as your backups.
>
> Not really, you have to consider the medium to which you are
> backing up.
> Now Tim did not mention the medium he uses, but I would guess he has
> DLT8000s.  Maybe just one.  He should be able to drive that
> puppy on an
> uncrippled N-class box at 12+MB/second.  You will notice this
> value is a lot
> less than either the read or write speed of the VA71xx.
>
> Given an uncrippled N-class and some proper backup software,
> you can expect
> a lot higher throughput rate going to LTO devices.  At that
> point, he might
> be able to do the backup of 500GB in less than 6 hours.
>
> I just looked at the original post and notice 2 things.  1-
> Tim did not
> mention how much data he is talking about, just 19 hours for
> backup.  2- The
> listing did show 38 volumes in the set.  I suggest he may not
> want quite
> that many on the VA71xx, maybe 16.
>
> If Tim uses a DLT8000 to do his backups, he has at most 800GB
> of data; if he
> uses (shudder) DDS-3 to do the backup, he has much less data, around
> 400-500GB at most.  Compression will help especially in the
> case of massive
> IMAGE databases.
>
> Denys
>
> -----Original Message-----
> From: Craig Lalley [mailto:[log in to unmask]]
> Sent: Monday, February 21, 2005 8:59 PM
> To: [log in to unmask]; [log in to unmask]
> Subject: Re: Moving from XP512 to VA71xx
>
>
> --- Denys Beauchemin <[log in to unmask]> wrote:
> >
> > And if your restore takes twice as long as your backup, you have
> > opportunities for improvement.
> >
>
> Denys,
>
> I think you have an excellent idea of moving one group at a time.
>
> Given that there is 500Gb of data to move accross a 1GB fiber
> path... Where
> is the real
> bottleneck?
>
> Relatively speaking, I would find it hard to believe that on
> a 1GB fiber
> path, it would really
> take that long to transfer the data.
>
> So what is the REAL throughput of a 1GB channel?
>
> -Craig
>
>
>
>
> __________________________________
> Do you Yahoo!?
> Yahoo! Mail - Easier than ever with enhanced search. Learn more.
> http://info.mail.yahoo.com/mail_250
>
> * To join/leave the list, search archives, change list settings, *
> * etc., please visit http://raven.utc.edu/archives/hp3000-l.html *

* To join/leave the list, search archives, change list settings, *
* etc., please visit http://raven.utc.edu/archives/hp3000-l.html *