Re: backup/amflush oddity
On Wed, 27 Sep 2006 at 9:06am, Jeff Portwine wrote However, I've noticed that every time Amanda doesn't find a writeable tape (usually due to the tape not being changed that day) there is very little data written to the holding disk and the amflush is very very small. The day after this, the dump is much larger than usual compensating for this. When we change the tapes every day, each tape is usually around 50% full. On a day when we forget to change the tape or are unable to change the tape the amflush results in about 0.5% tape useage, and the day following the day we did the amflush tape useage is usually 85-90%. Is this how it's supposed to behave? How can I fix it to do a normal dump to the holding disk on days when either we can't change the tape or we forget to change the tape? Read up on the 'reserve' parameter in amanda.conf, its default value, and its effects on degraded mode dumps. -- Joshua Baker-LePain Department of Biomedical Engineering Duke University
Re: backup/amflush oddity
On Wed, Sep 27, 2006 at 09:06:32AM -0400, Jeff Portwine enlightened us: Hoping somebody can clarify something about amanda for me. I have my backups set to run on a 3 day dump cycle with 6 tapes, running every evening except sunday night. It seems to work fine, we change the tape each morning so over the course of a week (if I understand how amanda works right) we get two sets of full backups. Sometimes we forget to change a tape, and most Saturdays we don't have anybody here to change the tape so on those days I thought that Amanda just backed up to the holding disk and then the next morning we could just change the tape, do an amflush, then change the tape again so that it would be ready for the next night. However, I've noticed that every time Amanda doesn't find a writeable tape (usually due to the tape not being changed that day) there is very little data written to the holding disk and the amflush is very very small. The day after this, the dump is much larger than usual compensating for this. When we change the tapes every day, each tape is usually around 50% full. On a day when we forget to change the tape or are unable to change the tape the amflush results in about 0.5% tape useage, and the day following the day we did the amflush tape useage is usually 85-90%. Is this how it's supposed to behave? How can I fix it to do a normal dump to the holding disk on days when either we can't change the tape or we forget to change the tape? Thanks for any explanation and/or tips. What settings do you have for your holding disk in amanda.conf? Specifically the reserve setting. Matt -- Matt Hyclak Department of Mathematics Department of Social Work Ohio University (740) 593-1263
Re: backup/amflush oddity
On Wednesday 27 September 2006 09:06, Jeff Portwine wrote: Hi everybody, Hoping somebody can clarify something about amanda for me. I have my backups set to run on a 3 day dump cycle with 6 tapes, running every evening except sunday night.It seems to work fine, we change the tape each morning so over the course of a week (if I understand how amanda works right) we get two sets of full backups.Sometimes we forget to change a tape, and most Saturdays we don't have anybody here to change the tape so on those days I thought that Amanda just backed up to the holding disk and then the next morning we could just change the tape, do an amflush, then change the tape again so that it would be ready for the next night. However, I've noticed that every time Amanda doesn't find a writeable tape (usually due to the tape not being changed that day) there is very little data written to the holding disk and the amflush is very very small. The day after this, the dump is much larger than usual compensating for this.When we change the tapes every day, each tape is usually around 50% full.On a day when we forget to change the tape or are unable to change the tape the amflush results in about 0.5% tape useage, and the day following the day we did the amflush tape useage is usually 85-90%. Is this how it's supposed to behave? How can I fix it to do a normal dump to the holding disk on days when either we can't change the tape or we forget to change the tape? Thanks for any explanation and/or tips. -Jeff Look up the keyword reserved as its used in amanda.conf, the default if not specified there is 100%. And the holding disk must, for this to work correctly, be larger than the tape. I believe some combination of the above is silently effecting your backups. I try to hold about 150% of a tapes size for holding space, with a reserve of 30% IIRC. -- Cheers, Gene There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order. -Ed Howdershelt (Author) Yahoo.com and AOL/TW attorneys please note, additions to the above message by Gene Heskett are: Copyright 2006 by Maurice Eugene Heskett, all rights reserved.
Re: backup/amflush oddity
Thank you for the pointer, I think that may be what I needed... will see how the backups go the rest of this week. -Jeff Read up on the 'reserve' parameter in amanda.conf, its default value, and its effects on degraded mode dumps.
Re: backup/amflush oddity
Thanks for the responses... I did a search on the reserve keyword and read up on it, and I'm pretty sure this is what I was missing. I didn't have any reserve set, so it was defaulting to 100%. I changed that to 30%. My holding disk is ~65GB and i'm using 20/40GB travan tapes so I think this will fix it.Thanks again for pointing me in the right direction. -Jeff - Original Message - From: Gene Heskett [EMAIL PROTECTED] To: amanda-users@amanda.org Sent: Wednesday, September 27, 2006 11:11 AM Subject: Re: backup/amflush oddity On Wednesday 27 September 2006 09:06, Jeff Portwine wrote: Hi everybody, Hoping somebody can clarify something about amanda for me. I have my backups set to run on a 3 day dump cycle with 6 tapes, running every evening except sunday night.It seems to work fine, we change the tape each morning so over the course of a week (if I understand how amanda works right) we get two sets of full backups.Sometimes we forget to change a tape, and most Saturdays we don't have anybody here to change the tape so on those days I thought that Amanda just backed up to the holding disk and then the next morning we could just change the tape, do an amflush, then change the tape again so that it would be ready for the next night. However, I've noticed that every time Amanda doesn't find a writeable tape (usually due to the tape not being changed that day) there is very little data written to the holding disk and the amflush is very very small. The day after this, the dump is much larger than usual compensating for this.When we change the tapes every day, each tape is usually around 50% full.On a day when we forget to change the tape or are unable to change the tape the amflush results in about 0.5% tape useage, and the day following the day we did the amflush tape useage is usually 85-90%. Is this how it's supposed to behave? How can I fix it to do a normal dump to the holding disk on days when either we can't change the tape or we forget to change the tape? Thanks for any explanation and/or tips. -Jeff Look up the keyword reserved as its used in amanda.conf, the default if not specified there is 100%. And the holding disk must, for this to work correctly, be larger than the tape. I believe some combination of the above is silently effecting your backups. I try to hold about 150% of a tapes size for holding space, with a reserve of 30% IIRC. -- Cheers, Gene There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order. -Ed Howdershelt (Author) Yahoo.com and AOL/TW attorneys please note, additions to the above message by Gene Heskett are: Copyright 2006 by Maurice Eugene Heskett, all rights reserved.
