Koji Uno wrote: > Hi, > > NEC who are the contributor of ARM code, provided their outcomes > of study to us. > > The size of ZFS runtime memory is measured by > - Dump content of runtime memory into file after booting > - Work it out by NEC internal tool > - Accumulate values of kmem > > Without changes of disk structure, they confirmed that the > consumption of ZFS runtime memory could be reduced to 8MB. > The ARC was limited to 4MB and it was minimum value in this > case. > > When the disk structure was changed as follows, further reduction > was realized. It resulted in 1MB ARC and 2MB ZFS runtime memory. > > - The size of dnode_phys_t structure was changed 512B into 256B. > > * See dnode_phys_t in uts/common/fs/zfs/sys/dnode.h > with uts/common/fs/czfs/sys/dnode.h > * See blkptr_t in uts/common/fs/zfs/sys/spa.h > with uts/common/fs/czfs/sys/spa.h
This change means that CZFS can't support crypto in the same way that ZFS does and that IMO is really bad. An encrypted ZFS is highly desirable for embedded systems (think an ARM powered smartphone!). I can work around this but again it makes it different to ZFS and that isn't good. > * See znode_phys_t in uts/common/fs/zfs/sys/zfs_znode.h > with uts/common/fs/czfs/sys/zfs_znode.h This is going to be changing soon anyway because of another project, I'll let the person working on it speak up if they wish to discuss that in public just now. -- Darren J Moffat
