So I've currently got a backup server with OMV + Snapraid and I would like some feedback on the usage I am doing..
I currently open it once per week to backup some files, when I am done I sync and I turn it off. I was wondering should I be doing something else? And how often should I scrub?
I also want to reorganize some of my stuff (move files around, rename and delete some) what is the best way to do that without messing up sync etc?
Thanks!
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after a successful "sync", you shoud make a check with "scrub - p new". This verifies, that everything was syncd correctly.
SnapRAID should recognize, if some files were moved. Sometimes it is required to do a "touch" command in snapraid (to set sub second timestamp).
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Thank you for the reply! Since I have never done a scrub yet (already 20TB on my backup server) what scrub command would you suggest me to run for the first time now?
Thanks!
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you can use "scrub -p 5" for scrubbing 5% of the data. if you do "scrub - p new" all data will be scrubbed since you did it never ('new' means just scrub just added/modified data).
The percentage scrubbing should be done time by time.
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I would like to know if this command "scrub - p new" goes at the same speed as synchronization? Or faster? Because I have 70tb of data, the sync lasts 6 days (8 HDDs in an 8-bay box), and if it is to wait another 6 days, I would not do it.
thx
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that is, why you should do a "scrub -p new" after a sync immediatly (delta sync, same speed for both). and later you should do a "scrub -p <num>", which will scrub a percentage of the array. This should be done to detect silent bit errors time by time. A "scrub -p 1" should work for about one and a half hour.</num>
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since only the first sync takes so much time, any further sync should be fast (since only delta is handled). Same is true for scrubbing (if everything was already scrubbed at least once except delta). You should scrubt the array, maybe 5% every night? than everything would be scrubbed in 3 weeks.
how is your bay connected to the computer? I think this connection is making snapraid so slow.
6 days for 70TB means about 141MB/s. That is usually the speed of a single disk. Normally snapraid accesses all disk in parallel.
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Yes you are right, it is slow, because the box is connected in usb3 to the PC, suddenly, the speed is divided by 8 since there are 8 HDDs in the 8 bays box.
Is it important to start the scrub? if I don't, what do I risk? knowing no new data would be saved to the HDDs.
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One last question, if I add a new HDD (in total 9 HDDs), and I synchronize everything, will the synchronization synchronize everything? or just sync the HDD I added?
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if you add an additional disc, all parity must be recalculated for the size of the disk data (since one more source, empty space does not count). Since then you have nine disks, it would take more than a week to sync everything (a full ninth disk).
the good news, scrubing will still be only for delta.
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Heya guys,
So I've currently got a backup server with OMV + Snapraid and I would like some feedback on the usage I am doing..
I currently open it once per week to backup some files, when I am done I sync and I turn it off. I was wondering should I be doing something else? And how often should I scrub?
I also want to reorganize some of my stuff (move files around, rename and delete some) what is the best way to do that without messing up sync etc?
Thanks!
after a successful "sync", you shoud make a check with "scrub - p new". This verifies, that everything was syncd correctly.
SnapRAID should recognize, if some files were moved. Sometimes it is required to do a "touch" command in snapraid (to set sub second timestamp).
Thank you for the reply! Since I have never done a scrub yet (already 20TB on my backup server) what scrub command would you suggest me to run for the first time now?
Thanks!
you can use "scrub -p 5" for scrubbing 5% of the data. if you do "scrub - p new" all data will be scrubbed since you did it never ('new' means just scrub just added/modified data).
The percentage scrubbing should be done time by time.
Hello,
I would like to know if this command "scrub - p new" goes at the same speed as synchronization? Or faster? Because I have 70tb of data, the sync lasts 6 days (8 HDDs in an 8-bay box), and if it is to wait another 6 days, I would not do it.
thx
Yes, it does.
that is, why you should do a "scrub -p new" after a sync immediatly (delta sync, same speed for both). and later you should do a "scrub -p <num>", which will scrub a percentage of the array. This should be done to detect silent bit errors time by time. A "scrub -p 1" should work for about one and a half hour.</num>
Thank you for your answers.
What would be ideal for you to do after a complete synchronization?
since only the first sync takes so much time, any further sync should be fast (since only delta is handled). Same is true for scrubbing (if everything was already scrubbed at least once except delta). You should scrubt the array, maybe 5% every night? than everything would be scrubbed in 3 weeks.
how is your bay connected to the computer? I think this connection is making snapraid so slow.
6 days for 70TB means about 141MB/s. That is usually the speed of a single disk. Normally snapraid accesses all disk in parallel.
Yes you are right, it is slow, because the box is connected in usb3 to the PC, suddenly, the speed is divided by 8 since there are 8 HDDs in the 8 bays box.
Is it important to start the scrub? if I don't, what do I risk? knowing no new data would be saved to the HDDs.
the scrubbing is done to detect silent errors on protected data. scrubbing may detect errors which could be fixed with help of the parity.
just reading the data would result in reading wrong data.
see http://www.snapraid.it/faq#guidelines and http://www.snapraid.it/faq#checksuminfo
Thanks for the feedback.
One last question, if I add a new HDD (in total 9 HDDs), and I synchronize everything, will the synchronization synchronize everything? or just sync the HDD I added?
if you add an additional disc, all parity must be recalculated for the size of the disk data (since one more source, empty space does not count). Since then you have nine disks, it would take more than a week to sync everything (a full ninth disk).
the good news, scrubing will still be only for delta.
Thank you for these responses.