Re: [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 [EMAIL PROTECTED] 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, Robertmailto:[EMAIL PROTECTED] http://milek.blogspot.com - Be a PS3 game guru. Get your game face on with the latest PS3 news and previews at Yahoo! Games.___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Re: [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
--
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`- Sysadmin at {cs,acc}.umu.se
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Re: [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/[EMAIL PROTECTED] (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 600508b400102eb70001204b 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 ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Re: [zfs-discuss] 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:[EMAIL PROTECTED] http://milek.blogspot.com ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
