Date: Wed, 11 May 2016 09:12:18 +0200 From: Edward Tomasz =?utf-8?Q?Napiera=C5=82a?= <trasz@FreeBSD.org> To: Matthew Grooms <mgrooms@shrew.net> Cc: freebsd-current@freebsd.org Subject: Re: Resizing a zpool as a VMware ESXi guest ... Message-ID: <20160511071218.GC5193@brick> In-Reply-To: <157c5d41-41c2-8812-79f1-3cab2c1eb8e5@shrew.net> References: <543841B8.4070007@shrew.net> <20141016081016.GA4670@brick.home> <5657F135.6080902@shrew.net> <56581F5A.4010009@digiware.nl> <56589C1A.1020702@shrew.net> <5658A764.5030508@shrew.net> <565906E8.9060005@shrew.net> <565A425C.7020101@shrew.net> <565A7906.60106@shrew.net> <157c5d41-41c2-8812-79f1-3cab2c1eb8e5@shrew.net>
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On 0510T1522, Matthew Grooms wrote: > On 11/28/2015 10:03 PM, Matthew Grooms wrote: > > On 11/28/2015 6:10 PM, Matthew Grooms wrote: > >> On 11/27/2015 7:44 PM, Matthew Grooms wrote: > >>> I spent the day looking over the FreeBSD cam and scsi_da source code. > >>> After sprinkling a bunch of printf's around to see what code paths > >>> were being called, It's obvious that Edward was correct in assuming > >>> that ESXi doesn't return any 'Unit Attention' sense information in > >>> response to a 'Read Capacity' request. This kinda makes sense as ESXi > >>> emulates SCSI-2 disk devices and, as far as I can tell, the 0x2A/0x09 > >>> ASC/ASCQ sense code that denotes 'Capacity Data Has Changed' wasn't > >>> defined until the SCSCI-3 spec. It's frustrating that the only way to > >>> get the scsci_da code to call reprobe() is by receiving a command > >>> from the device. Would something like this work? ... > >>> > >>> 1) Register a callback using xpt_register_async( daasync, > >>> AC_REPROBE_DEVICE, path ) that calls reprobe() > >>> 2) Implement a new IOCTL in cam_xpt that camcontrol can call with the > >>> bus:target:lun as the argument > >>> 3) have cam_xpt capture the IOCTL request and call xpt_async( > >>> AC_REPROBE_DEVICE, path ) as a result > >>> > >>> This way users would have the option of manually asking cam to > >>> communicate the new size to geom. The only option now is one or more > >>> reboots to gain access to the increased disk capacity. If this sounds > >>> like a reasonable approach, I'll take a stab at implementing it. > >>> > >> > >> Here is a proof of concept patch. I'm a complete noob when it comes to > >> cam, scsi or freebsd kernel development for that matter, so I'm sure > >> it could have been done a better way. In any case, I added a new > >> command to camcontrol that allows you to specify a bus, target and lun > >> as an argument. For example ... > >> > >> # camcontrol readcap da1 -h > >> Device Size: 32 G, Block Length: 512 bytes > >> > >> # gpart show da1 > >> => 40 58720176 da1 GPT (28G) > >> 40 58720176 1 freebsd-ufs (28G) > >> > >> Note, I resized the VMDK disk in ESXi. The camcontrol output shows the > >> size as 32G but geom thinks its 28G. > >> > >> # camcontrol devlist > >> <NECVMWar VMware IDE CDR10 1.00> at scbus1 target 0 lun 0 (cd0,pass0) > >> <VMware Virtual disk 1.0> at scbus2 target 0 lun 0 (pass1,da0) > >> <VMware Virtual disk 1.0> at scbus2 target 1 lun 0 (pass2,da1) > >> <FREEBSD CTLDISK 0001> at scbus3 target 0 lun 0 (da2,pass3) > >> > >> # camcontrol reprobe 2:1:0 > >> > >> This generates an event that is captured by the scsci da device to > >> forces a reprobe. The kernel output looks almost identical to when the > >> 'Unit Attention' sense data is received ... > >> > >> Nov 28 17:46:13 iscsi-i kernel: (da1:mpt0:0:1:0): Re-probe requested > >> Nov 28 17:46:13 iscsi-i kernel: GEOM_PART: da1 was automatically resized. > >> Nov 28 17:46:13 iscsi-i kernel: Use `gpart commit da1` to save changes > >> or `gpart undo da1` to revert them. > >> > >> Now that geom knows about the increased disk capacity, I can increase > >> the partition size and grow the fs ... > >> > >> [root@iscsi-i /home/mgrooms]# gpart show da1 > >> => 40 67108784 da1 GPT (32G) > >> 40 58720176 1 freebsd-ufs (28G) > >> 58720216 8388608 - free - (4.0G) > >> > >> # gpart resize -i 1 da1 > >> da1p1 resized > >> > >> # growfs da1p1 > >> Device is mounted read-write; resizing will result in temporary write > >> suspension for /var/data1. > >> It's strongly recommended to make a backup before growing the file > >> system. > >> OK to grow filesystem on /dev/da1p1, mounted on /var/data1, from 28GB > >> to 32GB? [Yes/No] Yes > >> super-block backups (for fsck_ffs -b #) at: > >> 58983232, 60265472, 61547712, 62829952, 64112192, 65394432, 66676672 > >> > >> # df -h > >> Filesystem Size Used Avail Capacity Mounted on > >> /dev/da0p3 18G 5.3G 12G 31% / > >> devfs 1.0K 1.0K 0B 100% /dev > >> /dev/da1p1 31G 32M 28G 0% /var/data1 > >> /dev/da2p1 15G 32M 14G 0% /var/data2 > >> > >> Sure would be nice to have something like this in the tree. It's > >> really a drag to have to reboot production VMs to increase disk > >> capacity when it could be easily avoided. I'm not sure what the > >> correct IOCTL should look like. Maybe CAMIOCOMMAND is a better way to > >> go? If someone with some experience with the cam/scsi subsystems was > >> willing to give me some direction I'd be willing to try and rewrite > >> the patch in a way that would be commit worthy. I just need some > >> direction. > >> > > > > Ok, last post until I get some feedback. Here's a new version of the > > patch complete with man page updates. It communicates via CAMIOCOMMAND > > instead of introducing a new ioctl value. I tried to model it after the > > device reset option, hopefully with some degree of success. Functionally > > it should be the same as the first patch. > > > > The PR 204901 filed for this can be closed now that the author (ahem) > has committed support for the camcontrol reprobe command ... > > https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=204901 > https://docs.freebsd.org/cgi/getmsg.cgi?fetch=866020+0+current/svn-src-head Ugh. I honestly have no idea how did I manage to miss your patch. I did remember the discussion, I remember asking mav@ about what's the best way to hook it up to CAM, but until yesterday I just didn't know the patch (and the PR) existed. Sorry for that. Guess that's what happens when I try to keep up with too many unrelated subprojects at the same time.
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