nanog mailing list archives
Re: Data Center testing
From: James Hess <mysidia () gmail com>
Date: Tue, 25 Aug 2009 23:46:42 -0500
On Tue, Aug 25, 2009 at 7:53 AM, Jeff Aitken<jaitken () aitken com> wrote:
[..] Periodically inducing failures to catch [...] them is sorta like using your smoke detector as an oven timer. [..] machine-parsable format, but the benefit is that you know in pseudo-realtime when something is wrong, as opposed to finding out the next time a device fails.
Config checking can't say much about silent hardware failures. Unanticipated problems are likely to arise in failover systems, especially complicated ones. A failover system that has not been periodically verified may not work as designed. Simulations, config review, and change controls are not substitutes for testing, they address overlapping but different problems. Testing detects unanticipated error; config review is a preventive measure that helps avoid and correct apparent configuration issues. Config checking (both software and hardware choices) also help to keep out unnecessary complexity. A human still has to write the script and review its output -- an operator error would eventually occur that is an accidental omission from both the current state and from the "desired" state; there is a chance that an erroneous entry escapes detection. There can be other types of errors: Possibly there is a damaged patch cable, dying port, failing power supply, or other hardware on the warm spare that has silently degraded and its poor condition won't be detected (until it actually tries to take a heavy workload, blows a fuse, eats a transceiver, and everything just falls apart). Perhaps you upgraded a hardware module or software image X months ago, to fix bug Y on the secondary unit, and the upgrade caused completely unanticipated side effect Z. Config checking can't say much about silent hardware problems. -- -Mysid
Current thread:
- Data Center testing Dan Snyder (Aug 24)
- RE: [SPAM-HEADER] - Data Center testing - Email has different SMTP TO: and MIME TO: fields in the email addresses Rod Beck (Aug 24)
- Re: Data Center testing Ken Gilmour (Aug 24)
- Re: Data Center testing Dan Snyder (Aug 24)
- Re: Data Center testing Jack Bates (Aug 24)
- Re: Data Center testing eric clark (Aug 25)
- Re: Data Center testing Jeff Aitken (Aug 25)
- RE: Data Center testing Frank Bulk - iName.com (Aug 25)
- Re: Data Center testing Jeff Aitken (Aug 26)
- Re: Data Center testing Dan Snyder (Aug 24)
- Re: Data Center testing James Hess (Aug 25)
- Re: Data Center testing Jack Bates (Aug 26)
- Re: Data Center testing Ross Vandegrift (Aug 26)
- RE: Data Center testing Dylan Ebner (Aug 26)
- RE: Data Center testing Deepak Jain (Aug 26)
- Re: Data Center testing Matthew Palmer (Aug 27)
- Re: Data Center testing Warren Kumari (Aug 26)
- Re: Data Center testing Seth Mattinen (Aug 24)
- RE: Data Center testing Deepak Jain (Aug 24)