On 8/31/2006 12:59 PM, Tom Schmidt wrote:
On Thu, 31 Aug 2006 11:27:53 -0400, Alan Altmark wrote:
They drives encrypt/decrypt data *in the drive itself tape speed*. The
performance penalty of host-based encryption is no longer necessary.
Hmmm... not quite. From the U.S. announcement materials:
"Note: With encryption enabled, the access time to data on the tape drive
will increase. Also, the tape drive unload time will increase. This is due
to the time needed to retrieve, read, and write the encryption key."
It appears that there *is* a performance penalty, although hopefully not as
severe as today (when the general processors have to do the work). Too bad
that wasn't offloaded to zIIPs/zAAPs/zEEPs ("Enhanced Encryption
Processor" - I just made that up) to generalize the support somehow.
Yes, there's a penalty (as encryption always costs something). But note
that the encryption does not happen in the host, and thus "offloading"
to zIIP/zAAP/whatever does not really apply.
The encryption is in the drive (or controller?) itself, which has
several advantages:
(1) It should be able to work in conjunction with hardware compression
(compress, then encrypt). That would not be possible if the encryption
happened in the host before sending the data to the tape.
(2) It works for more than just z/OS or System z. From the
announcement, it supports: IBM System z™, System i™, System p™,
System x™, and can be used with a wide range of Linux on System z, Sun,
and Hewlett Packard servers, and Linux-based servers, as well as
Intel®-compatible servers running Linux, Microsoft™ Windows 2000, or
Windows Server 2003.
Walt
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