Re: RSYNC & INFORMIX
Hari Gupta wrote: > > Question about rsync and Informix. > > Many of you may be using rsync to sync or backup their servers which > has a beauty of sending ONLY changes in data across network. That's' > fine. Hari, I believe you might be one of our customers. If the name Conrad means anything to you, please talk to him straight away so he can slap you across the phone until you promise to stop thinking these evil thoughts. Basically, RUBBISH. Don't do this. Where did this ridiculous idea come from?
Andrew Hamm" <ahamm@mail.com> wrote in message news:<2lgmj3Fch085U1@uni-berlin.de>... > Hari Gupta wrote: > > > > Question about rsync and Informix. > > > > Many of you may be using rsync to sync or backup their servers which > > has a beauty of sending ONLY changes in data across network. That's' > > fine. > > Hari, I believe you might be one of our customers. If the name Conrad means > anything to you, please talk to him straight away so he can slap you across > the phone until you promise to stop thinking these evil thoughts. >> Andrew, I have been reading your comments from last so many years. Most >> of the time, I find very good technical input from your comments, however, >> some time notice your comments very offensive as well. Yes, we are your >> customer unfortunately and suffering with RUBBISH support and crap product >> design. In many cases, your customers are not HAPPY at all and looking for >> some better solution. People laugh when we talk about your support >> and product. Anyway, this is not a plateform to discuss. > Basically, RUBBISH. Don't do this. Where did this ridiculous idea come from? >> As you will be aware that this beautiful piece of software was probably >> develepoed by Andrew Tridgell which very smartly backups files by >> transferring only changes in the data (NOT THE ENTIRE FILE). We are >> using this without any issue for backing up our servers (not the database), >> where as a crap solution is being sold by your company. Please note, my >> comments are not personal to any one. >> RSYNC ALGORITHM: >> The rsync algorithm consists of the following steps: >> 1. splits the file into a series of non-overlapping fixed-sized blocks >> of size S bytes1. The last block may be shorter than S bytes. >> 2. For each of these blocks calculates two checksums: a weak ``rolling'' >> 32-bit checksum and a strong 128-bit MD4 checksum. >> 3. sends these checksums >> 4. searches through A to find all blocks of length S bytes (at any offset, >> not just multiples of S) that have the same weak and strong checksum as one >> of the blocks of B. This can be done in a single pass very quickly using a >> special property of the rolling checksum. >> 5. sends a sequence of instructions for constructing a copy of A. Each >> instruction is either a reference to a block of B, or literal data. Literal >> data is sent only for those sections of A which did not match any of the >> blocks of B. >> The end result is that gets a copy of A, but only the pieces of A that are >> not found in B (plus a small amount of data for checksums and block >> indexes) are sent over the link. The algorithm also only requires one round >> trip, which minimises the impact of the link latency. >> The most important details of the algorithm are the rolling checksum and >> the associated multi-alternate search mechanism which allows the all- >> offsets checksum search to proceed very quickly. >> To find out more about RSYNC algorithm, Pl. have a look at below URL: >> http://samba.anu.edu.au/rsync/tech_report/node2.html >> We just wanted to have comments from community if any one has done some >> work or thoghts with RSYNC & INFORMIX.
Andrew Hamm" <ahamm@mail.com> wrote in message news:<2lgmj3Fch085U1@uni-berlin.de>... > Hari Gupta wrote: > > > > Question about rsync and Informix. > > > > Many of you may be using rsync to sync or backup their servers which > > has a beauty of sending ONLY changes in data across network. That's' > > fine. > > Hari, I believe you might be one of our customers. If the name Conrad means > anything to you, please talk to him straight away so he can slap you across > the phone until you promise to stop thinking these evil thoughts. >> Andrew, I have been reading your comments from last so many years. Most >> of the time, I find very good technical input from your comments, however, >> some time notice your comments very offensive as well. Yes, we are your >> customer unfortunately and suffering with RUBBISH support and crap product >> design. In many cases, your customers are not HAPPY at all and looking for >> some better solution. People laugh when we talk about your support >> and product. Anyway, this is not a plateform to discuss. > Basically, RUBBISH. Don't do this. Where did this ridiculous idea come from? >> As you will be aware that this beautiful piece of software was probably >> develepoed by Andrew Tridgell which very smartly backups files by >> transferring only changes in the data (NOT THE ENTIRE FILE). We are >> using this without any issue for backing up our servers (not the database), >> where as a crap solution is being sold by your company. Please note, my >> comments are not personal to any one. >> RSYNC ALGORITHM: >> The rsync algorithm consists of the following steps: >> 1. splits the file into a series of non-overlapping fixed-sized blocks >> of size S bytes1. The last block may be shorter than S bytes. >> 2. For each of these blocks calculates two checksums: a weak ``rolling'' >> 32-bit checksum and a strong 128-bit MD4 checksum. >> 3. sends these checksums >> 4. searches through A to find all blocks of length S bytes (at any offset, >> not just multiples of S) that have the same weak and strong checksum as one >> of the blocks of B. This can be done in a single pass very quickly using a >> special property of the rolling checksum. >> 5. sends a sequence of instructions for constructing a copy of A. Each >> instruction is either a reference to a block of B, or literal data. Literal >> data is sent only for those sections of A which did not match any of the >> blocks of B. >> The end result is that gets a copy of A, but only the pieces of A that are >> not found in B (plus a small amount of data for checksums and block >> indexes) are sent over the link. The algorithm also only requires one round >> trip, which minimises the impact of the link latency. >> The most important details of the algorithm are the rolling checksum and >> the associated multi-alternate search mechanism which allows the all- >> offsets checksum search to proceed very quickly. >> To find out more about RSYNC algorithm, Pl. have a look at below URL: >> http://samba.anu.edu.au/rsync/tech_report/node2.html >> We just wanted to have comments from community if any one has done some >> work or thoghts with RSYNC & INFORMIX.