On 1/23/2015 2:33 PM, Heitor Faria wrote: >> On 01/23/2015 12:22 PM, Radosław Korzeniewski wrote: >> >>> If you are using a vchanger then I guess it is a disk only backup, so why >>> do you spool data? It is not required but making you backup slow down at >>> least 2 times then standard job. >> It's 2 times slower if your spool/despool is strictly sequential and the >> same size pipes go in and out. If you have 10 clients spooling over a >> 1Gb/s link, that's roughly 10MB/s/client. Iostat clocks ext4/basic sata >> drives at around 110MB/s write speed, so despooling is 10 times faster. >> If only the clients could keep the pipe full, it could be ~10 times >> faster than the "standard" job. In a purely hypothetical perfectly >> spherical world of uniform density, obviously, but still: no, 2x slow >> down is not how it really works. > Even though, IMHO, spooling disks backup is just "muda" (Japanese Term): > http://en.wikipedia.org/wiki/Muda_(Japanese_term)
No. It is not wasteful if it serves a purpose. The goal is to get the client's part in the job done faster. Fast storage is expensive. A shared spool area on fast disk gets the clients part done faster, and then the SD can de-spool to slower (and cheaper) volume file storage without affecting the client. Using spooling for disk volumes is exactly the same reasoning as using it for tape volumes. ------------------------------------------------------------------------------ New Year. New Location. New Benefits. New Data Center in Ashburn, VA. GigeNET is offering a free month of service with a new server in Ashburn. Choose from 2 high performing configs, both with 100TB of bandwidth. Higher redundancy.Lower latency.Increased capacity.Completely compliant. http://p.sf.net/sfu/gigenet _______________________________________________ Bacula-users mailing list Bacula-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bacula-users
