Re: Defer-Write with L1 and L2
Posted: Tue Oct 26, 2021 6:50 am
Right. I misread. I also meant to make L2 defer-write 100% no loss, able to recover data after a crash.Support wrote: ↑Tue Oct 26, 2021 3:59 amCurrently, whether using L1 or L2, max data loss = latency (though it is possible that lost data is updated file system metadata by chance). What we think and other users request is to make L2 defer-write 100% no loss, able to recover data after a crash. That's complicated.Styx wrote: ↑Mon Oct 25, 2021 3:25 pm May I suggest an advanced option when Defer-write is enabled using an L2 cache ?
The option would be: "persist dirty block map" and when enabled, it would actually flush the dirty block map on the L2 cache (persistent) each time a time interval specified by Latency expires.
This way, it allows a user to use the defer-write with some level of protection against data loss (i.e max data loss = latency, so if you set latency to 5s, then you can lose up to 5s of data in case of a system crash).
I guess the problem is that system files would be changed on reboot before primocache can finish its job making it virtually impossible. But it can be solved by creating a primocache boot disk to complete the cache flush before starting windows