W dniu 2013-06-16 11:12, Mehrshad Manshadi pisze:
Hello all,
does anyone have a "rule of thumb" as to how much Replication for disaster
recovery slows down overall disk I/O?
We are replicating about 45 terabytes from HDS USP using asynch. We recently
had issues that slowed our mainframe to a crawl. The work around was to stop
replication. During the time replication was shut down our batch ran twice as
fast as it does with replication up.
In general there are two modes:
- "synch mode"
- "initial copy"
(note the terms are in quotation marks, becasue they are not accurate).
"synch mode" means everything is synchronized and only current I/O
updates are replicated. In this mode there is big difference between
synchronous and asynchronous remote copy. Synchronous is slows down your
DASD, especially during I/O intensive operations like batch.
IMHO in normal circumstances asynchronous remote copy should not slow
down your dasd box considerably, nevermind what dasd brandname you use..
"initial copy" is "data pumping". Your DASD has to send all the data
from full of data BOX A (local) to BOX B (remote), which is initially
empty. It can be a lot of data, despite some part of the data is
inactive. This process always slows down your DASD box, despite what the
salesmen claimed. However in some implementations you can manage the
priority of the process. Lower priority means longer time to finish but
faster reponses from the DASD box. Sometimes it's better to use highest
priority during maint. window.
HTH
--
Radoslaw Skorupka
Lodz, Poland
--
Tre tej wiadomoci moe zawiera informacje prawnie chronione Banku
przeznaczone wycznie do uytku subowego adresata. Odbiorc moe by jedynie
jej adresat z wyczeniem dostpu osób trzecich. Jeeli nie jeste adresatem
niniejszej wiadomoci lub pracownikiem upowanionym do jej przekazania
adresatowi, informujemy, e jej rozpowszechnianie, kopiowanie, rozprowadzanie
lub inne dziaanie o podobnym charakterze jest prawnie zabronione i moe by
karalne. Jeeli otrzymae t wiadomo omykowo, prosimy niezwocznie
zawiadomi nadawc wysyajc odpowied oraz trwale usun t wiadomo
wczajc w to wszelkie jej kopie wydrukowane lub zapisane na dysku.
This e-mail may contain legally privileged information of the Bank and is intended solely for business use of the addressee. This e-mail may only be received by the addressee and may not be disclosed to any third parties. If you are not the intended addressee of this e-mail or the employee authorised to forward it to the addressee, be advised that any dissemination, copying, distribution or any other similar activity is legally prohibited and may be punishable. If you received this e-mail by mistake please advise the sender immediately by using the reply facility in your e-mail software and delete permanently this e-mail including any copies of it either printed or saved to hard drive.
BRE Bank SA, 00-950 Warszawa, ul. Senatorska 18, tel. +48 (22) 829 00 00, fax
+48 (22) 829 00 33, www.brebank.pl, e-mail: [email protected]
Sd Rejonowy dla m. st. Warszawy XII Wydzia Gospodarczy Krajowego Rejestru Sdowego, nr rejestru przedsibiorców KRS 0000025237, NIP: 526-021-50-88.
Wedug stanu na dzie 01.01.2013 r. kapita zakadowy BRE Banku SA (w caoci wpacony) wynosi 168.555.904 zotych.
----------------------------------------------------------------------
For IBM-MAIN subscribe / signoff / archive access instructions,
send email to [email protected] with the message: INFO IBM-MAIN
