Re: [zfs-discuss] ZFS percent busy vs zpool iostat
Quoting Bob Friesenhahn : What function is the system performing when it is so busy? The work load of the server is SMTP mail server, with associated spam and virus scanning, and serving maildir email via POP3 and IMAP. Wrong conclusion. I am not sure what the percentages are percentages of (total RAM?), but 603MB is a very small ARC. FreeBSD pre-assigns kernel memory for zfs so it is not dynamically shared with the kernel as it is with Solaris. This is the min, max, and actual size of the ARC. ZFS is free to use up to the MAX (2098.08M) if it decides it wants to. Depending on the work load on this server it will go up to 2098M (as in Ive seen it get to that size on this and other servers), just with its usual daily work load it decides to set this to around 600M. I assume it decides it's not worth using any more RAM. The ARC is "adaptive" so you should not assume that its objective is to try to absorb your hard drive. It should not want to cache data which is rarely accessed. Regardless, your ARC size may actually be constrained by default FreeBSD kernel tunings. I guess then that ZFS is weighing up how useful it is to use more than 600M and deciding that it isnt that useful? Anyway, Ive just forced the Min to 1900M so will see how this goes today. The type of drives you are using have very poor seek performance. Higher RPM drives would surely help. Stuffing lots more memory in your system and adjusting the kernel so that zfs can use a lot more of it is likely to help dramatically. Zfs loves memory. thanks Bob, and also to Matt for your comments... ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Re: [zfs-discuss] ZFS percent busy vs zpool iostat
Ok, think I have the biggest issue. The drives are 4k sector drives, and I wasn't aware of that. My fault, I should have checked this. Had the disks for ages and are sub 1TB so had the idea that they wouldn't be 4k drives... I will obviously have to address this, either by creating a pool using 4k aware zfs commands or replacing the disks. Anyway, thanks to all and to Taemun for getting me to check this... ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Re: [zfs-discuss] zpool scalability and performance
Basically I think yes you need to add all the vdevs you require in the circumstances you describe. You just have to consider what ZFS is able to do with the disks that you give it. If you have 4x mirrors to start with then all writes will be spread across all disks and you will get nice performance using all 8 spindles/disks. If you fill all of these up then add one other mirror then its logical that new data written will be only written to the free space on the new mirror and you will get the performance of writing data to a single mirrored vdev. To handle this you would either have to add sufficient new devices to give you your required performance. Or if there is a fair amount of data turn around on your pool, ie you are deleting (including from snapshots) old data then you might get reasonable performance by adding a new mirror at some point before your existing pool is completely full. Ie data will initially get written and spread across all disks as there will be free space on all disks, and over time old data will be removed from the other older vdevs. Which would result in most of the time reads and writes benefiting from all vdevs, but it't not going to give you guarantees of that I guess... Anyway, thats what occurred to me on the subject! ;) cheers Andy. ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Re: [zfs-discuss] Drive i/o anomaly
It is a 4k sector drive, but I thought zfs recognised those drives and didn't need any special configuration...? 4k drives are a big problem for ZFS, much has been posted/written about it. Basically, if the 4k drives report 512 byte blocks, as they almost all do, then ZFS does not detect and configure the pool correctly. If the drive actually reports the real 4k block size, ZFS handles this very nicely. So the problem/fault is drives misreporting the real block size, to maintain compatibility with other OS's etc, and not really with ZFS. cheers Andy. ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Re: [zfs-discuss] ZFS send/recv initial data load
On Feb 16, 2011, at 7:38 AM, whitetr6 at gmail.com wrote: My question is about the initial "seed" of the data. Is it possible to use a portable drive to copy the initial zfs filesystem(s) to the remote location and then make the subsequent incrementals over the network? If so, what would I need to do to make sure it is an exact copy? Thank you, Yes, you can send the initial seed snapshot to a file on a portable disk. for example: # zfs send tank/volume@seed > /myexternaldrive/zfssnap.data If the volume of data is too much to fit on a single disk then you can create a new pool spread across the number of disks you require, make a duplicate of the snapshot onto your new pool. Then from the new pool you can run a new zfs send when connected to your offsite server. thanks Andy. ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Re: [zfs-discuss] Solaris vs FreeBSD question
Hi, I am using FreeBSD 8.2 in production with ZFS. Although I have had one issue with it in the past but I would recommend it and I consider it production ready. That said if you can wait for FreeBSD 8.3 or 9.0 to come out (a few months away) you will get a better system as these will include ZFS v28 (FreeBSD-RELEASE is currently v15). On the other had things can always go wrong, of course RAID is not backup, even with snapshots ;) cheers Andy. ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Re: [zfs-discuss] Monitoring disk seeks
Hi, see the seeksize script on this URL: http://prefetch.net/articles/solaris.dtracetopten.html Not used it but looks neat! cheers Andy. ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Re: [zfs-discuss] ZFS, Oracle and Nexenta
Still i wonder what Gartner means with Oracle monetizing on ZFS.. It simply means that Oracle want to make money from ZFS (as is normal for technology companies with their own technology). The reason this might cause uncertainty for ZFS is that maintaining or helping make the open source version of ZFS better may be seen by Oracle as contradictory to them making money from it. That said, what is already open source cannot be un-open sourced, as others have said... cheers Andy. ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Re: [zfs-discuss] Question on ZFS iSCSI
Disk /dev/zvol/rdsk/pool/dcpool: 4295GB Sector size (logical/physical): 512B/512B Just to check, did you already try: zpool import -d /dev/zvol/rdsk/pool/ poolname ? thanks Andy. ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
