gkontos said:Sorry, what is not required ?
I have seen cases where the checksum has caused weird messages and false alarms. IMHO you are much better off without it.graudeejs said:It is not required to turn off checksum property.
However (turning it off might increase performance. I never noticed anything. So I decided to leave it on. At least I'll know when my disk start to die, even if it's swap area. I might be wrong )
gkontos said:I have seen cases where the checksum has caused weird messages and false alarms. IMHO you are much better off without it.
Crivens said:Have you heard that they are now removing the FriendOrFoe alert from missile systems? There have been weird beebing noises and false alarms...
Crivens said:Seriously, for all disks which gave out in my systems in the last years ZFS got the message way before SMART was able to find anything. The only benefit for turning off checksums for swap would be that a read error from the disk does not shoot up the system. Maybe the page is to be written, then you are save. But I do not play russian roulette. If it does not fail at once you get panics, maybe hours or days later, and have no idea where they come from.
Crivens said:Sorry if this seems harsh, but I see what a certain "this will work, 'guv" stance can get you into each day @work. Do the right thing, do not overdo it, consider each part to be a fail-waiting-to-happen. Including yourself.
Not for ZFS, there are others here who know more about what to do with it. Phenix comes to mind, for example.gkontos said:No, I haven't but I take your word for it since you seem to be the expert here
Yes, it checks your data. And it does this IMHO much better than the SMART code in the HD. You get the notification from ZFS that something does not work out before the HD sees anything wrong. You are free to ignore such warnings if you want.SMART has nothing to do with ZFS. SMART will report a failure only after the failure has occurred. ZFS also doesn't get any message from disks. It simply rely on checksums to check the integrity of data.
No. My point is that if you can have a warning that the disks are about to fail, I want that warning ASAP. Your suggestion to disable checksums to shave a few cycles would help how exactly?Your point is that while your data is being constantly checked by checksums, you rely on SWAP which is being used as an alternative to memory, as a tool for data integrity.
Yes, and proudly. There is a fundamental difference between a slow system and a crashed system. Also, if the pool which is hosting the swap device or file is supplying redundancy you can survive even a read error upon page-in. Again, it can do that only when checking is enabled.In addition you are adding extra hogs to a system at a time when the system is over loaded.
Which is more or less exactly what I wrote.My opinion and implementation is based upon technical facts and experience. Of course I could be wrong. But I at least I am not arrogant. I see the arrogance in some peoples work each time I am called to fix their catastrophes
graudeejs said:Right, and you expect swap to be use all the time... I don't I expect swap to not be used... If it's used too much, it means that you need more RAM
Slurp said:I have a workload that could benefit from petabytes of RAM. I can't afford it, so I push what I have. For this reason, in the predictable future my swap will be used heavily.