dudekula mastan
2007-Feb-03 07:31 UTC
[zfs-discuss] Which label a ZFS/ZPOOL device has ? VTOC or EFI ?
Hi All, ZPOOL / ZFS commands writes EFI label on a device if we create ZPOOL/ZFS fs on it. Is it true ? I formatted a device with VTOC lable and I created a ZFS file system on it. Now which label the ZFS device has ? is it old VTOC or EFI ? After creating the ZFS file system on a VTOC labeled disk, I am seeing the following warning messages. Feb 3 07:47:00 scoobyb Corrupt label; wrong magic number Feb 3 07:47:00 scoobyb scsi: [ID 107833 kern.warning] WARNING: /scsi_vhci/ssd at g600508b400102eb700012000004b0000 (ss d156): Any idea on this ? Your help is appreciated. Thanks & Regards Masthan --------------------------------- It''s here! Your new message! Get new email alerts with the free Yahoo! Toolbar. -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://mail.opensolaris.org/pipermail/zfs-discuss/attachments/20070202/e0ea10b2/attachment.html>
Robert Milkowski
2007-Feb-03 11:29 UTC
Re: Which label a ZFS/ZPOOL device has ? VTOC or EFI ?
Hello dudekula, Saturday, February 3, 2007, 8:31:24 AM, you wrote: > Hi All, ZPOOL / ZFS commands writes EFI label on a device if we create ZPOOL/ZFS fs on it. Is it true ? I formatted a device with VTOC lable and I created a ZFS file system on it. Now which label the ZFS device has ? is it old VTOC or EFI ? Depends how you''ve created pool. If during pool creation you''ve specified entire disk (c0t0d0 - without slice) then ZFS put EFI label. Now if you''ve specified slice then ZFS has just used that slice without changing anything to label. You can also check current label with format(1M) utility. -- Best regards, Robert mailto:rmilkowski@task.gda.pl http://milek.blogspot.com _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
dudekula mastan
2007-Feb-04 10:25 UTC
[zfs-discuss] Which label a ZFS/ZPOOL device has ? VTOC or EFI ?
Hi Robert, Thanks for your quick reply. As for as my knowledge concerns (because I am new to Solaris) the second slice (e.g. c0t0d0d2) of disk is exactly same to whole disk (e.g. c0t0d0). It means if we create ZPool on second slice it will create zpool on whole disk. For example the following two commands does the same job. $zpool create -f mypool c1t0d0 $zpool create -f mypool c1t0d0s2 How the label of the disk differs from first case ($zpool create -f mypool c1t0d0) to second case ($zpool create -f mypool c1t0d0s2). Thanks & Regards Masthan Robert Milkowski <rmilkowski at task.gda.pl> wrote: Hello dudekula, Saturday, February 3, 2007, 8:31:24 AM, you wrote: > Hi All, ZPOOL / ZFS commands writes EFI label on a device if we create ZPOOL/ZFS fs on it. Is it true ? I formatted a device with VTOC lable and I created a ZFS file system on it. Now which label the ZFS device has ? is it old VTOC or EFI ? Depends how you''ve created pool. If during pool creation you''ve specified entire disk (c0t0d0 - without slice) then ZFS put EFI label. Now if you''ve specified slice then ZFS has just used that slice without changing anything to label. You can also check current label with format(1M) utility. -- Best regards, Robert mailto:rmilkowski at task.gda.pl http://milek.blogspot.com --------------------------------- Be a PS3 game guru. Get your game face on with the latest PS3 news and previews at Yahoo! Games. -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://mail.opensolaris.org/pipermail/zfs-discuss/attachments/20070204/e8ec3af4/attachment.html>
Tomas Ögren
2007-Feb-04 12:46 UTC
[zfs-discuss] Which label a ZFS/ZPOOL device has ? VTOC or EFI ?
On 04 February, 2007 - dudekula mastan sent me these 7,5K bytes:> Hi Robert, > > Thanks for your quick reply. > > As for as my knowledge concerns (because I am new to Solaris) the > second slice (e.g. c0t0d0d2) of disk is exactly same to whole disk > (e.g. c0t0d0).Almost, but no.> It means if we create ZPool on second slice it will > create zpool on whole disk. > > For example the following two commands does the same job. > > > $zpool create -f mypool c1t0d0 > > $zpool create -f mypool c1t0d0s2 > > How the label of the disk differs from first case ($zpool create -f > mypool c1t0d0) to second case ($zpool create -f mypool c1t0d0s2).If the disk has VTOC label, there is no "c1t0d0".. ZFS will see that you''re "kinda" referring to the whole disk and change it into EFI. With the second version, you''re using a slice (that just happen to cover all of the disk) and it won''t change to EFI and won''t mess around with the write cache for additional performance. /Tomas -- Tomas ?gren, stric at acc.umu.se, http://www.acc.umu.se/~stric/ |- Student at Computing Science, University of Ume? `- Sysadmin at {cs,acc}.umu.se
Jonathan Edwards
2007-Feb-04 14:45 UTC
[zfs-discuss] Which label a ZFS/ZPOOL device has ? VTOC or EFI ?
On Feb 3, 2007, at 02:31, dudekula mastan wrote:> After creating the ZFS file system on a VTOC labeled disk, I am > seeing the following warning messages. > > Feb 3 07:47:00 scoobyb Corrupt label; wrong magic number > Feb 3 07:47:00 scoobyb scsi: [ID 107833 kern.warning] WARNING: / > scsi_vhci/ssd at g600508b400102eb700012000004b0000 (ssd156): > > Any idea on this ?This generally means that this device doesn''t have a label - and this particular device would be the multipathed device identified by the GUID 600508b400102eb700012000004b0000 or the old BSD style driver enumeration ssd156 .. (take a look at http://access1.sun.com/ codesamples/disknames.html to see an example on how to use libdevinfo to convert this to the SVR4 c#t#d# style name) Now with ZFS if you don''t specify a slice, you''re essentially asking ZFS to use and autolabel the entire disk which will put an EFI style label on since the older sun style VTOC labels have an upper limit of 1TB per disk (EFI should work up to 2^64 LBAs.) The older sun VTOC labels typically use slice 2 as a backup to show the entire disk and will store the label in the first 512B, whereas the EFI labels will use 34 sectors at the start of the disk to store the label, and will also reserve a portion at the tail end of the disk for a backup label. With the older sun style VTOC labels, if you ever overwrite the first the first 512B on cylinder 0 of the disk (eg: dd if=/dev/zero of=/dev/ rdsk/c1t1d0s2 where s2 is the typical backup label starting at cylinder 0) you''ll overwrite the label, whereas with the EFI label you have to overwrite both protected sections of the disk. So to reiterate what Robert and Tomas have already gone into .. if you plan on using the entire disk and want the vdev benefits (the ability to import/export pools, write caching, etc) you should probably not specify a slice and allow ZFS to autolabel the disk as it sees fit. hth ---- .je -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://mail.opensolaris.org/pipermail/zfs-discuss/attachments/20070204/12df1627/attachment.html>