Re: [zfs-discuss] Multiple filesystem costs? Directory sizes?
Mario, For the reasons you mentioned, having a few different filesystems (on the order of 5-10, I'd guess) can be handy. Any time you want different behavior for different types of data, multiple filesystems are the way to go. For maximum directory size, it turns out that the practical limits aren't in ZFS -- they're in your favorite applications, like ls(1) and file browsers. ZFS won't mind if you put millions of files in a directory, but ls(1) will be painfully slow. Similarly, if you're using a mail program and you go to a big directory to grab an attachment... you'll wait and wait while it reads the first few bytes of every file in the directory to determine its type. Hope that helps, Jeff Mario Goebbels wrote: While setting up my new system, I'm wondering whether I should go with plain directories or use ZFS filesystems for specific stuff. About the cost of ZFS filesystems, I read on some Sun blog in the past about something like 64k kernel memory (or whatever) per active filesystem. What are however the additional costs? The reason I'm considering multiple filesystems is for instance easy ZFS backups and snapshots, but also tuning the recordsizes. Like storing lots of generic pictures from the web, smaller recordsizes may be appropriate to trim down the waste once the filesize surpasses the record size, aswell as using large recordsizes for video files on a seperate filesystem. Turning on and off compression and access times for performance reasons are another thing. Also, in this same message, I'd like to ask what sensible maximum directory sizes are. As in amount of files. Thanks. This message posted from opensolaris.org ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Re: [zfs-discuss] Multiple filesystem costs? Directory sizes?
Mario Goebbels wrote: While setting up my new system, I'm wondering whether I should go with plain directories or use ZFS filesystems for specific stuff. About the cost of ZFS filesystems, I read on some Sun blog in the past about something like 64k kernel memory (or whatever) per active filesystem. What are however the additional costs? I don't think the resource costs are well characterized, yet. IMHO, you should only create file systems if you need to have different policies for the file systems. Search this forum for more discussion on this topic. The reason I'm considering multiple filesystems is for instance easy ZFS backups and snapshots, but also tuning the recordsizes. Like storing lots of generic pictures from the web, smaller recordsizes may be appropriate to trim down the waste once the filesize surpasses the record size, aswell as using large recordsizes for video files on a seperate filesystem. Turning on and off compression and access times for performance reasons are another thing. compression and atime settings are policies. recordsize could also be a policy, however, it seems to me that you are confused about ZFS and recordsize. The reason it exists is for those applications (eg. databases) which use a fixed recordsize and we want to match that record size to avoid doing extra work. For example, if the application recordsize is fixed at 8 kBytes, then we don't want to prefetch 129 kBytes (or 56 kBytes) as that could be wasted work. By default, ZFS will dynamically adjust its recordsize, which is probably what you want. Also, in this same message, I'd like to ask what sensible maximum directory sizes are. As in amount of files. Dunno. In theory, you could go until you run out of space. Several people have commented on their usage, so you can look in the archives. -- richard ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
[zfs-discuss] Multiple filesystem costs? Directory sizes?
While setting up my new system, I'm wondering whether I should go with plain directories or use ZFS filesystems for specific stuff. About the cost of ZFS filesystems, I read on some Sun blog in the past about something like 64k kernel memory (or whatever) per active filesystem. What are however the additional costs? The reason I'm considering multiple filesystems is for instance easy ZFS backups and snapshots, but also tuning the recordsizes. Like storing lots of generic pictures from the web, smaller recordsizes may be appropriate to trim down the waste once the filesize surpasses the record size, aswell as using large recordsizes for video files on a seperate filesystem. Turning on and off compression and access times for performance reasons are another thing. Also, in this same message, I'd like to ask what sensible maximum directory sizes are. As in amount of files. Thanks. This message posted from opensolaris.org ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
