Re: [CentOS] not using LVM for Linux VM guests?
On Sun, 20 Nov 2011, Smithies, Russell wrote: Nope, doesn't work for me still. It's the root partition I'm trying to resize so if I delete then recreate to larger size, partprobe still fails then if I reboot it won't start as it can't find the root partition. As Barry suggested, I don't think you can reread the root partition. Hang on, if you recreated root's partition at the same starting point it wouldn't struggle to find it would it? Are you *sure* you're making the partition in *exactly* the same place? I'm just wondering if the partition was carefully byte aligned, then you're just using fdisk and misplacing it? jh ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] not using LVM for Linux VM guests?
- Original Message - | Nope, doesn't work for me still. | It's the root partition I'm trying to resize so if I delete then | recreate to larger size, partprobe still fails then if I reboot it | won't start as it can't find the root partition. | As Barry suggested, I don't think you can reread the root partition. | | --Russell Considering that I've done this hundreds of times, I can only say that you must be doing it wrong. If you've delete the partition and then created the partition at the exact same starting point this should not have happened at all. As I said, you must have done something incorrectly. -- James A. Peltier IT Services - Research Computing Group Simon Fraser University - Burnaby Campus Phone : 778-782-6573 Fax : 778-782-3045 E-Mail : jpelt...@sfu.ca Website : http://www.sfu.ca/itservices http://blogs.sfu.ca/people/jpeltier I will do the best I can with the talent I have ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] not using LVM for Linux VM guests?
Nope, doesn't work for me still. It's the root partition I'm trying to resize so if I delete then recreate to larger size, partprobe still fails then if I reboot it won't start as it can't find the root partition. As Barry suggested, I don't think you can reread the root partition. --Russell -Original Message- From: centos-boun...@centos.org [mailto:centos-boun...@centos.org] On Behalf Of James A. Peltier Sent: Friday, 18 November 2011 6:29 p.m. To: CentOS mailing list Subject: Re: [CentOS] not using LVM for Linux VM guests? - Original Message - | I've tried that, it returns a warning about kernel unable to reread | partition table and requiring a reboot to see any modifications. | Then the next call to pvcreate fails as it can't find the partition. | | --Russell | | -Original Message- | From: centos-boun...@centos.org [mailto:centos- boun...@centos.org] | On | Behalf Of Barry Brimer | Sent: Friday, 18 November 2011 11:13 a.m. | To: CentOS mailing list | Subject: Re: [CentOS] not using LVM for Linux VM guests? | | Quoting Smithies, Russell russell.smith...@agresearch.co.nz: | | Perhaps I'm doing it wrong then. | | 1). In Vmware, extend the existing disk by changing the | provisioned size in the vSphere client. | 2). In Centos, create an additional partition with fdisk, 3). | Somehow | reread the partition table without rebooting?? | 4). pvcreate | 5). vgextend | 6). lvextend | 7). resize2fs | | What I find is that without a reboot, the OS doesn't see the | partition so can't pvcreate etc. | | --Russell | | I don't believe partprobe works when you change the partitiontable of | the disk that the root filesystem is on. I could be remembering it | wrong. | | Barry It does but it (the new size) is not recognized until you delete the partition, recreate it with the new size, then run partprobe again, then resize the file system. It's worked for me in the past. -- James A. Peltier IT Services - Research Computing Group Simon Fraser University - Burnaby Campus Phone : 778-782-6573 Fax : 778-782-3045 E-Mail : jpelt...@sfu.ca Website : http://www.sfu.ca/itservices http://blogs.sfu.ca/people/jpeltier I will do the best I can with the talent I have ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos === Attention: The information contained in this message and/or attachments from AgResearch Limited is intended only for the persons or entities to which it is addressed and may contain confidential and/or privileged material. Any review, retransmission, dissemination or other use of, or taking of any action in reliance upon, this information by persons or entities other than the intended recipients is prohibited by AgResearch Limited. If you have received this message in error, please notify the sender immediately. === ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] not using LVM for Linux VM guests?
On 11/16/2011 09:37 PM, Smithies, Russell wrote: I came across an old post comment yesterday (from http://echenh.blogspot.com/2010/04/how-to-extend-lvm-on-vmware-guest-os.html ) discussing the hack of LVM on Linux VM guests and whether it's better not to use it to simplify disk management. I've re-posted the comment below, does it sound reasonable? Is it better to not use LVM on Linux VM guests? --Russell --- At my job, after doing the same kind of procedure graph, we began to ask ourselves, why are using a LVM on a Linux VM guests? Since we're no longer living in the physical OS world, we didn't need to use the OS hacks(LVM) to overcome physical disk limitations anymore. We decided to Just let the hypervisor and virtual storage do that work for us. For example, in our production setup (3 tier commerce with VMs for database , webserver, and appserver), we're see a great improvement in managability and performance (10%) by just dropping LVM, and most partitions. In your example, the resize process is 7 functional steps: 1. Increase size of VMDK 2. In VM OS, Create Partition (??) 3. REBOOT (!!) 4. PVCreate 5. VGExtend 6. LVExtend 7. Resize2fs Going to a LVM/partition-less setup reduces expansion to 3 steps and we don't need to take the VM OS offline! 1. Increase size of VMDK 2- Inside the VM, OS, rescan the scsi drive with:'echo 1/sys/class/scsi_device//rescan; dmesg' (dmesg will check that you drive isize has grown) 3- Resize2fs. Our current disk arrangement has 3 VM HD devices 0 - small device (100M) with a single BOOT partition 1 - entire device is / 2 - entire device is SWAP Doing this has simplified resizing so much, I now let the junior admins and my manager expand drive space as needed. It's also let's us really be spartan on space since expansion is so quick. Instead of increasing systems in 30-50GB chunks, we can do 10-15GB and let our rmonitoring system warn us when space gets tight. I'm not sure what the exact setup is but on the standard CentOS 5 setup you can extend the space of a LVM-based guest without rebooting the guest. Just add another virtual disk and it will immediately appear in the guest. Set it up there as physical volume, add it to the main volume group and then resize2fs the root filesystem. No restart or downtime required. Regards, Dennis ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] not using LVM for Linux VM guests?
On Thu, 17 Nov 2011, Smithies, Russell wrote: I came across an old post comment yesterday (from http://echenh.blogspot.com/2010/04/how-to-extend-lvm-on-vmware-guest-os.html ) discussing the hack of LVM on Linux VM guests and whether it's better not to use it to simplify disk management. I've re-posted the comment below, does it sound reasonable? Is it better to not use LVM on Linux VM guests? --Russell --- At my job, after doing the same kind of procedure graph, we began to ask ourselves, why are using a LVM on a Linux VM guests? Since we're no longer living in the physical OS world, we didn't need to use the OS hacks(LVM) to overcome physical disk limitations anymore. We decided to Just let the hypervisor and virtual storage do that work for us. For example, in our production setup (3 tier commerce with VMs for database , webserver, and appserver), we're see a great improvement in managability and performance (10%) by just dropping LVM, and most partitions. In your example, the resize process is 7 functional steps: 1. Increase size of VMDK 2. In VM OS, Create Partition (??) 3. REBOOT (!!) 4. PVCreate 5. VGExtend 6. LVExtend 7. Resize2fs Going to a LVM/partition-less setup reduces expansion to 3 steps and we don't need to take the VM OS offline! 1. Increase size of VMDK 2- Inside the VM, OS, rescan the scsi drive with:'echo 1 /sys/class/scsi_device//rescan; dmesg' (dmesg will check that you drive isize has grown) 3- Resize2fs. Our current disk arrangement has 3 VM HD devices 0 - small device (100M) with a single BOOT partition 1 - entire device is / 2 - entire device is SWAP Doing this has simplified resizing so much, I now let the junior admins and my manager expand drive space as needed. It's also let's us really be spartan on space since expansion is so quick. Instead of increasing systems in 30-50GB chunks, we can do 10-15GB and let our rmonitoring system warn us when space gets tight. - One reason I choose to have separate filesystems which do use LVM instead of VMware disks is that I can use different mount options. For example my /tmp filesystems usually get noexec,nodev,nosuid .. with one root filesystem that contains everything, you can't use mount options as effectively. I also bind mount /var/tmp to /tmp for the same reason. Barry ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] not using LVM for Linux VM guests?
Hello, - Original Message - From: Russell Smithies russell.smith...@agresearch.co.nz To: CentOS mailing list centos@centos.org Sent: Wednesday, November 16, 2011 2:37:54 PM Subject: [CentOS] not using LVM for Linux VM guests? I came across an old post comment yesterday (from http://echenh.blogspot.com/2010/04/how-to-extend-lvm-on-vmware-guest-os.html ) discussing the hack of LVM on Linux VM guests and whether it's better not to use it to simplify disk management. I've re-posted the comment below, does it sound reasonable? Is it better to not use LVM on Linux VM guests? --Russell I've had the same question. I've decided to continue to use LVM, for these 2 reasons: 1) my hypervisor, good, bad or indifferent, is VMware ESX 4.x and ESXi 4.x. Those hypervisors can't create virtual disks greater than 256 GB. So, if I want a file-system larger than 256 GB, I have to have some other software - LVM, in this case. 2) I like being able to give disk devices descriptive names, like /dev/mapper/zimbra-data instead of simply '/dev/sdb' or similar. There are probably ways other than LVM to do that, but LVM does offer that flexibility. One thing I do avoid, however, is partitioning the virtual disks that might need to grow. This is because of the pain described in part below. The kernel often seems to have a hard time letting go of it's view of the partition table - either i have to umount the partition, or reboot. However, if i use the disk unpartitioned, the kernel has no prob, and I can *extend and/or resize*fs without umount or reboot. - Jon --- At my job, after doing the same kind of procedure graph, we began to ask ourselves, why are using a LVM on a Linux VM guests? Since we're no longer living in the physical OS world, we didn't need to use the OS hacks(LVM) to overcome physical disk limitations anymore. We decided to Just let the hypervisor and virtual storage do that work for us. For example, in our production setup (3 tier commerce with VMs for database , webserver, and appserver), we're see a great improvement in managability and performance (10%) by just dropping LVM, and most partitions. In your example, the resize process is 7 functional steps: 1. Increase size of VMDK 2. In VM OS, Create Partition (??) 3. REBOOT (!!) 4. PVCreate 5. VGExtend 6. LVExtend 7. Resize2fs Going to a LVM/partition-less setup reduces expansion to 3 steps and we don't need to take the VM OS offline! 1. Increase size of VMDK 2- Inside the VM, OS, rescan the scsi drive with:'echo 1 /sys/class/scsi_device//rescan; dmesg' (dmesg will check that you drive isize has grown) 3- Resize2fs. Our current disk arrangement has 3 VM HD devices 0 - small device (100M) with a single BOOT partition 1 - entire device is / 2 - entire device is SWAP Doing this has simplified resizing so much, I now let the junior admins and my manager expand drive space as needed. It's also let's us really be spartan on space since expansion is so quick. Instead of increasing systems in 30-50GB chunks, we can do 10-15GB and let our rmonitoring system warn us when space gets tight. - === Attention: The information contained in this message and/or attachments from AgResearch Limited is intended only for the persons or entities to which it is addressed and may contain confidential and/or privileged material. Any review, retransmission, dissemination or other use of, or taking of any action in reliance upon, this information by persons or entities other than the intended recipients is prohibited by AgResearch Limited. If you have received this message in error, please notify the sender immediately. === ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] not using LVM for Linux VM guests?
On Thu, 17 Nov 2011, Jon Detert wrote: One thing I do avoid, however, is partitioning the virtual disks that might need to grow. This is because of the pain described in part below. The kernel often seems to have a hard time letting go of it's view of the partition table - either i have to umount the partition, or reboot. However, if i use the disk unpartitioned, the kernel has no prob, and I can *extend and/or resize*fs without umount or reboot. I think that's the main message to take away from this. There's no obvious benefit of having partitions over having whole disks. jh ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] not using LVM for Linux VM guests?
On 11/17/2011 11:13 AM, Jon Detert wrote: Hello, - Original Message - From: Russell Smithiesrussell.smith...@agresearch.co.nz To: CentOS mailing listcentos@centos.org Sent: Wednesday, November 16, 2011 2:37:54 PM Subject: [CentOS] not using LVM for Linux VM guests? I came across an old post comment yesterday (from http://echenh.blogspot.com/2010/04/how-to-extend-lvm-on-vmware-guest-os.html ) discussing the hack of LVM on Linux VM guests and whether it's better not to use it to simplify disk management. I've re-posted the comment below, does it sound reasonable? Is it better to not use LVM on Linux VM guests? --Russell I've had the same question. I've decided to continue to use LVM, for these 2 reasons: 1) my hypervisor, good, bad or indifferent, is VMware ESX 4.x and ESXi 4.x. Those hypervisors can't create virtual disks greater than 256 GB. So, if I want a file-system larger than 256 GB, I have to have some other software - LVM, in this case. Just to clarify one thing with large virtual disks. The size limitation is determined by the block size. To create a file bigger than 256GB, the VMFS filesystem needs to have a block size larger than 1MB. These are the maximums: VMFS-3 (ESX/ESXi 4.x) Block Size Maximum File Size 1 MB - 256 GB (default) 2 MB - 512 GB 4 MB - 1 TB 8 MB - 2 TB http://kb.vmware.com/kb/1003565 With VMFS-5 has a maximum virtual disk size of 2TB minus 512B, with a 1 MB block size. Cheers, Paul ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] not using LVM for Linux VM guests?
-Original Message- From: centos-boun...@centos.org [mailto:centos-boun...@centos.org] On Behalf Of Jon Detert Sent: Friday, 18 November 2011 5:13 a.m. To: CentOS mailing list Subject: Re: [CentOS] not using LVM for Linux VM guests? Hello, - Original Message - From: Russell Smithies russell.smith...@agresearch.co.nz To: CentOS mailing list centos@centos.org Sent: Wednesday, November 16, 2011 2:37:54 PM Subject: [CentOS] not using LVM for Linux VM guests? I came across an old post comment yesterday (from http://echenh.blogspot.com/2010/04/how-to-extend-lvm-on-vmware- guest-o s.html ) discussing the hack of LVM on Linux VM guests and whether it's better not to use it to simplify disk management. I've re-posted the comment below, does it sound reasonable? Is it better to not use LVM on Linux VM guests? --Russell I've had the same question. I've decided to continue to use LVM, for these 2 reasons: 1) my hypervisor, good, bad or indifferent, is VMware ESX 4.x and ESXi 4.x. Those hypervisors can't create virtual disks greater than 256 GB. So, if I want a file-system larger than 256 GB, I have to have some other software - LVM, in this case. 2) I like being able to give disk devices descriptive names, like /dev/mapper/zimbra-data instead of simply '/dev/sdb' or similar. There are probably ways other than LVM to do that, but LVM does offer that flexibility. One thing I do avoid, however, is partitioning the virtual disks that might need to grow. This is because of the pain described in part below. The kernel often seems to have a hard time letting go of it's view of the partition table - either i have to umount the partition, or reboot. However, if i use the disk unpartitioned, the kernel has no prob, and I can *extend and/or resize*fs without umount or reboot. - Jon I have the same problem - I can never get the partition table reread without a reboot. It's a little annoying as I can resize the disk on a Win2k8 VM without a reboot but not Linux :-( --Russell === Attention: The information contained in this message and/or attachments from AgResearch Limited is intended only for the persons or entities to which it is addressed and may contain confidential and/or privileged material. Any review, retransmission, dissemination or other use of, or taking of any action in reliance upon, this information by persons or entities other than the intended recipients is prohibited by AgResearch Limited. If you have received this message in error, please notify the sender immediately. === ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] not using LVM for Linux VM guests?
-Original Message- From: centos-boun...@centos.org [mailto:centos-boun...@centos.org] On Behalf Of Paul Griffith Sent: Friday, 18 November 2011 8:04 a.m. To: centos@centos.org Subject: Re: [CentOS] not using LVM for Linux VM guests? On 11/17/2011 11:13 AM, Jon Detert wrote: Hello, - Original Message - From: Russell Smithiesrussell.smith...@agresearch.co.nz To: CentOS mailing listcentos@centos.org Sent: Wednesday, November 16, 2011 2:37:54 PM Subject: [CentOS] not using LVM for Linux VM guests? I came across an old post comment yesterday (from http://echenh.blogspot.com/2010/04/how-to-extend-lvm-on-vmware- guest- os.html ) discussing the hack of LVM on Linux VM guests and whether it's better not to use it to simplify disk management. I've re-posted the comment below, does it sound reasonable? Is it better to not use LVM on Linux VM guests? --Russell I've had the same question. I've decided to continue to use LVM, for these 2 reasons: 1) my hypervisor, good, bad or indifferent, is VMware ESX 4.x and ESXi 4.x. Those hypervisors can't create virtual disks greater than 256 GB. So, if I want a file-system larger than 256 GB, I have to have some other software - LVM, in this case. Just to clarify one thing with large virtual disks. The size limitation is determined by the block size. To create a file bigger than 256GB, the VMFS filesystem needs to have a block size larger than 1MB. These are the maximums: VMFS-3 (ESX/ESXi 4.x) Block Size Maximum File Size 1 MB - 256 GB (default) 2 MB - 512 GB 4 MB - 1 TB 8 MB - 2 TB http://kb.vmware.com/kb/1003565 With VMFS-5 has a maximum virtual disk size of 2TB minus 512B, with a 1 MB block size. Cheers, Paul I just did the vSphere 5 What's New course and it looked they'd pumped all the maximums up to usable levels now. Be nice if they could decide on a licensing model that made more sense... --Russell === Attention: The information contained in this message and/or attachments from AgResearch Limited is intended only for the persons or entities to which it is addressed and may contain confidential and/or privileged material. Any review, retransmission, dissemination or other use of, or taking of any action in reliance upon, this information by persons or entities other than the intended recipients is prohibited by AgResearch Limited. If you have received this message in error, please notify the sender immediately. === ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] not using LVM for Linux VM guests?
Am 17.11.2011 20:25, schrieb Smithies, Russell: I have the same problem - I can never get the partition table reread without a reboot. It's a little annoying as I can resize the disk on a Win2k8 VM without a reboot but not Linux :-( Next time simply use the partprobe command. --Russell Alexander ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] not using LVM for Linux VM guests?
Tried that, as well as rescanning the scsi bus, Everything I've tried returns a warning about kernel unable to reread partition table and requiring a reboot to see any modifications. --Russell -Original Message- From: centos-boun...@centos.org [mailto:centos-boun...@centos.org] On Behalf Of Alexander Dalloz Sent: Friday, 18 November 2011 9:07 a.m. To: CentOS mailing list Subject: Re: [CentOS] not using LVM for Linux VM guests? Am 17.11.2011 20:25, schrieb Smithies, Russell: I have the same problem - I can never get the partition table reread without a reboot. It's a little annoying as I can resize the disk on a Win2k8 VM without a reboot but not Linux :-( Next time simply use the partprobe command. --Russell Alexander ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos === Attention: The information contained in this message and/or attachments from AgResearch Limited is intended only for the persons or entities to which it is addressed and may contain confidential and/or privileged material. Any review, retransmission, dissemination or other use of, or taking of any action in reliance upon, this information by persons or entities other than the intended recipients is prohibited by AgResearch Limited. If you have received this message in error, please notify the sender immediately. === ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] not using LVM for Linux VM guests?
Am 17.11.2011 22:36, schrieb Smithies, Russell: Tried that, as well as rescanning the scsi bus, Everything I've tried returns a warning about kernel unable to reread partition table and requiring a reboot to see any modifications. gparted does tell you this since years after modify but i have never in my life rebooted a linux system because partition changes signature.asc Description: OpenPGP digital signature ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] not using LVM for Linux VM guests?
Perhaps I'm doing it wrong then. 1). In Vmware, extend the existing disk by changing the provisioned size in the vSphere client. 2). In Centos, create an additional partition with fdisk, 3). Somehow reread the partition table without rebooting?? 4). pvcreate 5). vgextend 6). lvextend 7). resize2fs What I find is that without a reboot, the OS doesn't see the partition so can't pvcreate etc. --Russell -Original Message- From: centos-boun...@centos.org [mailto:centos-boun...@centos.org] On Behalf Of Reindl Harald Sent: Friday, 18 November 2011 10:48 a.m. To: centos@centos.org Subject: Re: [CentOS] not using LVM for Linux VM guests? Am 17.11.2011 22:36, schrieb Smithies, Russell: Tried that, as well as rescanning the scsi bus, Everything I've tried returns a warning about kernel unable to reread partition table and requiring a reboot to see any modifications. gparted does tell you this since years after modify but i have never in my life rebooted a linux system because partition changes === Attention: The information contained in this message and/or attachments from AgResearch Limited is intended only for the persons or entities to which it is addressed and may contain confidential and/or privileged material. Any review, retransmission, dissemination or other use of, or taking of any action in reliance upon, this information by persons or entities other than the intended recipients is prohibited by AgResearch Limited. If you have received this message in error, please notify the sender immediately. === ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] not using LVM for Linux VM guests?
Quoting Smithies, Russell russell.smith...@agresearch.co.nz: Perhaps I'm doing it wrong then. 1). In Vmware, extend the existing disk by changing the provisioned size in the vSphere client. 2). In Centos, create an additional partition with fdisk, 3). Somehow reread the partition table without rebooting?? 4). pvcreate 5). vgextend 6). lvextend 7). resize2fs What I find is that without a reboot, the OS doesn't see the partition so can't pvcreate etc. --Russell -Original Message- From: centos-boun...@centos.org [mailto:centos-boun...@centos.org] On Behalf Of Reindl Harald Sent: Friday, 18 November 2011 10:48 a.m. To: centos@centos.org Subject: Re: [CentOS] not using LVM for Linux VM guests? Am 17.11.2011 22:36, schrieb Smithies, Russell: Tried that, as well as rescanning the scsi bus, Everything I've tried returns a warning about kernel unable to reread partition table and requiring a reboot to see any modifications. gparted does tell you this since years after modify but i have never in my life rebooted a linux system because partition changes Step 3 .. run partprobe. ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] not using LVM for Linux VM guests?
I've tried that, it returns a warning about kernel unable to reread partition table and requiring a reboot to see any modifications. Then the next call to pvcreate fails as it can't find the partition. --Russell -Original Message- From: centos-boun...@centos.org [mailto:centos-boun...@centos.org] On Behalf Of Barry Brimer Sent: Friday, 18 November 2011 11:13 a.m. To: CentOS mailing list Subject: Re: [CentOS] not using LVM for Linux VM guests? Quoting Smithies, Russell russell.smith...@agresearch.co.nz: Perhaps I'm doing it wrong then. 1). In Vmware, extend the existing disk by changing the provisioned size in the vSphere client. 2). In Centos, create an additional partition with fdisk, 3). Somehow reread the partition table without rebooting?? 4). pvcreate 5). vgextend 6). lvextend 7). resize2fs What I find is that without a reboot, the OS doesn't see the partition so can't pvcreate etc. --Russell -Original Message- From: centos-boun...@centos.org [mailto:centos-boun...@centos.org] On Behalf Of Reindl Harald Sent: Friday, 18 November 2011 10:48 a.m. To: centos@centos.org Subject: Re: [CentOS] not using LVM for Linux VM guests? Am 17.11.2011 22:36, schrieb Smithies, Russell: Tried that, as well as rescanning the scsi bus, Everything I've tried returns a warning about kernel unable to reread partition table and requiring a reboot to see any modifications. gparted does tell you this since years after modify but i have never in my life rebooted a linux system because partition changes Step 3 .. run partprobe. ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos === Attention: The information contained in this message and/or attachments from AgResearch Limited is intended only for the persons or entities to which it is addressed and may contain confidential and/or privileged material. Any review, retransmission, dissemination or other use of, or taking of any action in reliance upon, this information by persons or entities other than the intended recipients is prohibited by AgResearch Limited. If you have received this message in error, please notify the sender immediately. === ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] not using LVM for Linux VM guests?
I've tried that, it returns a warning about kernel unable to reread partition table and requiring a reboot to see any modifications. Then the next call to pvcreate fails as it can't find the partition. --Russell -Original Message- From: centos-boun...@centos.org [mailto:centos-boun...@centos.org] On Behalf Of Barry Brimer Sent: Friday, 18 November 2011 11:13 a.m. To: CentOS mailing list Subject: Re: [CentOS] not using LVM for Linux VM guests? Quoting Smithies, Russell russell.smith...@agresearch.co.nz: Perhaps I'm doing it wrong then. 1). In Vmware, extend the existing disk by changing the provisioned size in the vSphere client. 2). In Centos, create an additional partition with fdisk, 3). Somehow reread the partition table without rebooting?? 4). pvcreate 5). vgextend 6). lvextend 7). resize2fs What I find is that without a reboot, the OS doesn't see the partition so can't pvcreate etc. --Russell I don't believe partprobe works when you change the partitiontable of the disk that the root filesystem is on. I could be remembering it wrong. Barry ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] not using LVM for Linux VM guests?
- Original Message - | I've tried that, it returns a warning about kernel unable to reread | partition table and requiring a reboot to see any modifications. | Then the next call to pvcreate fails as it can't find the partition. | | --Russell | | -Original Message- | From: centos-boun...@centos.org [mailto:centos-boun...@centos.org] | On | Behalf Of Barry Brimer | Sent: Friday, 18 November 2011 11:13 a.m. | To: CentOS mailing list | Subject: Re: [CentOS] not using LVM for Linux VM guests? | | Quoting Smithies, Russell russell.smith...@agresearch.co.nz: | | Perhaps I'm doing it wrong then. | | 1). In Vmware, extend the existing disk by changing the | provisioned | size in the vSphere client. | 2). In Centos, create an additional partition with fdisk, 3). | Somehow | reread the partition table without rebooting?? | 4). pvcreate | 5). vgextend | 6). lvextend | 7). resize2fs | | What I find is that without a reboot, the OS doesn't see the | partition | so can't pvcreate etc. | | --Russell | | I don't believe partprobe works when you change the partitiontable of | the | disk that the root filesystem is on. I could be remembering it wrong. | | Barry It does but it (the new size) is not recognized until you delete the partition, recreate it with the new size, then run partprobe again, then resize the file system. It's worked for me in the past. -- James A. Peltier IT Services - Research Computing Group Simon Fraser University - Burnaby Campus Phone : 778-782-6573 Fax : 778-782-3045 E-Mail : jpelt...@sfu.ca Website : http://www.sfu.ca/itservices http://blogs.sfu.ca/people/jpeltier I will do the best I can with the talent I have ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
[CentOS] not using LVM for Linux VM guests?
I came across an old post comment yesterday (from http://echenh.blogspot.com/2010/04/how-to-extend-lvm-on-vmware-guest-os.html ) discussing the hack of LVM on Linux VM guests and whether it's better not to use it to simplify disk management. I've re-posted the comment below, does it sound reasonable? Is it better to not use LVM on Linux VM guests? --Russell --- At my job, after doing the same kind of procedure graph, we began to ask ourselves, why are using a LVM on a Linux VM guests? Since we're no longer living in the physical OS world, we didn't need to use the OS hacks(LVM) to overcome physical disk limitations anymore. We decided to Just let the hypervisor and virtual storage do that work for us. For example, in our production setup (3 tier commerce with VMs for database , webserver, and appserver), we're see a great improvement in managability and performance (10%) by just dropping LVM, and most partitions. In your example, the resize process is 7 functional steps: 1. Increase size of VMDK 2. In VM OS, Create Partition (??) 3. REBOOT (!!) 4. PVCreate 5. VGExtend 6. LVExtend 7. Resize2fs Going to a LVM/partition-less setup reduces expansion to 3 steps and we don't need to take the VM OS offline! 1. Increase size of VMDK 2- Inside the VM, OS, rescan the scsi drive with:'echo 1 /sys/class/scsi_device//rescan; dmesg' (dmesg will check that you drive isize has grown) 3- Resize2fs. Our current disk arrangement has 3 VM HD devices 0 - small device (100M) with a single BOOT partition 1 - entire device is / 2 - entire device is SWAP Doing this has simplified resizing so much, I now let the junior admins and my manager expand drive space as needed. It's also let's us really be spartan on space since expansion is so quick. Instead of increasing systems in 30-50GB chunks, we can do 10-15GB and let our rmonitoring system warn us when space gets tight. - === Attention: The information contained in this message and/or attachments from AgResearch Limited is intended only for the persons or entities to which it is addressed and may contain confidential and/or privileged material. Any review, retransmission, dissemination or other use of, or taking of any action in reliance upon, this information by persons or entities other than the intended recipients is prohibited by AgResearch Limited. If you have received this message in error, please notify the sender immediately. === ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] not using LVM for Linux VM guests?
We use who disk LVM on our VMs. No partitioning except for the root disk which is separate for all our VMs. Since for us the root disks are largely static and all other components are on the full disk LVM volumes growing them doesn't require a reboot at all. Just rescan the scsi bus and resize. Done! - Original Message - | I came across an old post comment yesterday (from | http://echenh.blogspot.com/2010/04/how-to-extend-lvm-on-vmware-guest-os.html | ) discussing the hack of LVM on Linux VM guests and whether it's | better not to use it to simplify disk management. | I've re-posted the comment below, does it sound reasonable? Is it | better to not use LVM on Linux VM guests? | | --Russell | | | --- | At my job, after doing the same kind of procedure graph, we began to | ask ourselves, why are using a LVM on a Linux VM guests? | | Since we're no longer living in the physical OS world, we didn't need | to use the OS hacks(LVM) to overcome physical disk limitations | anymore. | We decided to Just let the hypervisor and virtual storage do that work | for us. | | For example, in our production setup (3 tier commerce with VMs for | database , webserver, and appserver), we're see a great improvement in | managability and performance (10%) by just dropping LVM, and most | partitions. | | In your example, the resize process is 7 functional steps: | 1. Increase size of VMDK | 2. In VM OS, Create Partition (??) | 3. REBOOT (!!) | 4. PVCreate | 5. VGExtend | 6. LVExtend | 7. Resize2fs | | Going to a LVM/partition-less setup reduces expansion to 3 steps and | we don't need to take the VM OS offline! | 1. Increase size of VMDK | 2- Inside the VM, OS, rescan the scsi drive with:'echo 1 | /sys/class/scsi_device//rescan; dmesg' (dmesg will check that you | drive isize has grown) | 3- Resize2fs. | | Our current disk arrangement has 3 VM HD devices | 0 - small device (100M) with a single BOOT partition | 1 - entire device is / | 2 - entire device is SWAP | | Doing this has simplified resizing so much, I now let the junior | admins and my manager expand drive space as needed. | | It's also let's us really be spartan on space since expansion is so | quick. Instead of increasing systems in 30-50GB chunks, we can do | 10-15GB and let our rmonitoring system warn us when space gets tight. | - | | === | Attention: The information contained in this message and/or | attachments | from AgResearch Limited is intended only for the persons or entities | to which it is addressed and may contain confidential and/or | privileged | material. Any review, retransmission, dissemination or other use of, | or | taking of any action in reliance upon, this information by persons or | entities other than the intended recipients is prohibited by | AgResearch | Limited. If you have received this message in error, please notify the | sender immediately. | === | ___ | CentOS mailing list | CentOS@centos.org | http://lists.centos.org/mailman/listinfo/centos -- James A. Peltier IT Services - Research Computing Group Simon Fraser University - Burnaby Campus Phone : 778-782-6573 Fax : 778-782-3045 E-Mail : jpelt...@sfu.ca Website : http://www.sfu.ca/itservices http://blogs.sfu.ca/people/jpeltier I will do the best I can with the talent I have ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
