Re: [SLUG] LVM
2009/5/15 fos...@tpg.com.au Quoting Daniel Bush dlb.id...@gmail.com: 2009/5/15 fos...@tpg.com.au - LVM is really cool and well worth the time to rad up on it. I am now going to LVM my home system. I'm planning to do this as well. I was thinking back to Mary's backup post last year and thinking if I could do lvm snapshots with an external harddrive. Still a bit new to lvm though. I think you have to install the alternate ubuntu cd to get lvm right? (unless you are using the server install instead of the desktop). The distinction between desktop and server in ubuntu is an install option not anything else. To add lvm to your existing system just 'apt-get install lvm2'. Aware of this. Just weighing up whether to do a clean install so that is why I think I have to use alternate instead of desktop. To convert an existing setup to lvm you have to have some free space (partitions or whole harddisks to use). First create a volume group (chunk of hardisk spread across one or more harddrives) sudo lvm pvdiskscan pvcreate /dev/yourpartions vgcreate vg1 /dev/part1 /dev/part2 create a logical volume somewhere in that volume group (say 300 gig named yourname in vg1) lvcreate -L300G -n yourname vg1 You can then mksfs.ext3 /dev/vg1/yourname (replace ext3 with whatever is appropriate) and then mount it. Since I've got you on this subject and maybe others reading this: I was working with a test server using vmware esx. It runs on a virtual disk which is just a file. I decided to resize the file to a larger size which created a whole bunch of extra space at the end of the disk. I made this an lvm partition (/dev/sda4) using fdisk and then I did something stupid which was to run mke2fs directly on /dev/sda4. I then tried to add this as a physical volume to my existing volume group and then extend one of the existing logical volumes. So far so dumb, right. So now lvm tells me I've got X gigs and df -h tells me I've got Y gigs (the old number). I think all I have to do is resize the existing fs on the logical volume (/dev/vg1/lv1) . I'm thinking there won't be any trouble because even though /dev/sda4 had some sort of file system added to it (even though it was an lvm partition), it never got used. But not sure if running mke2fs on /dev/sda4 has/will bork something. (This is just a test system) On a separate issue: Is it safe to grow a root/bootable ext3 partition or do I have to unmount it - the resize2fs man page doesn't say anything but I read somewhere that I had to unmount and use a rescue disk (maybe this was just for ext2)? And I also assumed I had to remove the journal, resize, check and then add the journal. Is XFS a better solution for server lvm stuff and for growing? - or maybe even JFS ?? -- Daniel Bush http://blog.web17.com.au -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] LVM
2009/5/15 fos...@tpg.com.au The distinction between desktop and server in ubuntu is an install option not anything else. To add lvm to your existing system just 'apt-get install lvm2'. To convert an existing setup to lvm you have to have some free space (partitions or whole harddisks to use). That's probably the way to convert an existing system to LVM. If you want to install Ubuntu with LVM straight away then it's a bit more tricky since the LVM package is not included in the installation CD so you have to: 1. Boot live cd. 2. open shell 3. apt-get install lvm2 4. insmod dm_mod 5. create PV, VG, LV's. Remember that you need to keep /boot on a regular partition since grub can't read LVM. (I can't remember off the top of my head now whether the GUI installer will support creation of LV's once it finds PV's and VG's. In any case it will be able to recognize the LV's and allow creation of filesystem/swap partitions on top of them). 6. install system from live to hard disk 7. mount -bind ... special filesystems (proc, sys, dev) under the hard-disk mount point 8. mount /boot under the right mount point on hard disk (the above two steps are required because the lvm package install kernel modules and run initramfs) 9. chroot to the hard disk partition 10. apt-get install lvm2 again on the hard disk. That's more or less it. --Amos -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] LVM
2009/5/15 Amos Shapira amos.shap...@gmail.com 2009/5/15 fos...@tpg.com.au The distinction between desktop and server in ubuntu is an install option not anything else. To add lvm to your existing system just 'apt-get install lvm2'. To convert an existing setup to lvm you have to have some free space (partitions or whole harddisks to use). That's probably the way to convert an existing system to LVM. If you want to install Ubuntu with LVM straight away then it's a bit more tricky since the LVM package is not included in the installation CD so you have to: 1. Boot live cd. 2. open shell 3. apt-get install lvm2 4. insmod dm_mod 5. create PV, VG, LV's. Remember that you need to keep /boot on a regular partition since grub can't read LVM. (I can't remember off the top of my head now whether the GUI installer will support creation of LV's once it finds PV's and VG's. In any case it will be able to recognize the LV's and allow creation of filesystem/swap partitions on top of them). 6. install system from live to hard disk 7. mount -bind ... special filesystems (proc, sys, dev) under the hard-disk mount point 8. mount /boot under the right mount point on hard disk (the above two steps are required because the lvm package install kernel modules and run initramfs) 9. chroot to the hard disk partition 10. apt-get install lvm2 again on the hard disk. That's more or less it. That sounds fraught. Are you sure I can't just go with the alternate cd which will walk me thru lvm and still give me a desktop kernel/system? -- Daniel Bush http://blog.web17.com.au -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] LVM
2009/5/15 Daniel Bush dlb.id...@gmail.com 2009/5/15 fos...@tpg.com.au Quoting Daniel Bush dlb.id...@gmail.com: 2009/5/15 fos...@tpg.com.au - LVM is really cool and well worth the time to rad up on it. I am now going to LVM my home system. I'm planning to do this as well. I was thinking back to Mary's backup post last year and thinking if I could do lvm snapshots with an external harddrive. Still a bit new to lvm though. I think you have to install the alternate ubuntu cd to get lvm right? (unless you are using the server install instead of the desktop). The distinction between desktop and server in ubuntu is an install option not anything else. To add lvm to your existing system just 'apt-get install lvm2'. Aware of this. Just weighing up whether to do a clean install so that is why I think I have to use alternate instead of desktop. To convert an existing setup to lvm you have to have some free space (partitions or whole harddisks to use). First create a volume group (chunk of hardisk spread across one or more harddrives) sudo lvm pvdiskscan pvcreate /dev/yourpartions vgcreate vg1 /dev/part1 /dev/part2 create a logical volume somewhere in that volume group (say 300 gig named yourname in vg1) lvcreate -L300G -n yourname vg1 You can then mksfs.ext3 /dev/vg1/yourname (replace ext3 with whatever is appropriate) and then mount it. Since I've got you on this subject and maybe others reading this: I was working with a test server using vmware esx. It runs on a virtual disk which is just a file. I decided to resize the file to a larger size which created a whole bunch of extra space at the end of the disk. I made this an lvm partition (/dev/sda4) using fdisk and then I did something stupid which was to run mke2fs directly on /dev/sda4. I then tried to add this as a physical volume to my existing volume group and then extend one of the existing logical volumes. So far so dumb, right. So now lvm tells me I've got X gigs and df -h tells me I've got Y gigs (the old number). I think all I have to do is resize the existing fs on the logical volume (/dev/vg1/lv1) . I'm thinking there won't be any trouble because even though /dev/sda4 had some sort of file system added to it (even though it was an lvm partition), it never got used. But not sure if running mke2fs on /dev/sda4 has/will bork something. (This is just a test system) On a separate issue: Is it safe to grow a root/bootable ext3 partition or do I have to unmount it - the resize2fs man page doesn't say anything but I read What I meant to say was grow the root ext3 fs which is on the bootable first partition . somewhere that I had to unmount and use a rescue disk (maybe this was just for ext2)? And I also assumed I had to remove the journal, resize, check and then add the journal. Is XFS a better solution for server lvm stuff and for growing? - or maybe even JFS ?? Found this thread on file systems: http://linux.derkeiler.com/Mailing-Lists/Debian/2008-01/msg01789.html Guess I'm sticking with ext3 for the moment. -- Daniel Bush http://blog.web17.com.au -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] LVM
Daniel Bush wrote: That sounds fraught. Are you sure I can't just go with the alternate cd which will walk me thru lvm and still give me a desktop kernel/system? Indeed you can. You can even download the alternate CD with jigdo! Cheers, -- Steve Wrong is endian little that knows everyone but. - Sam Hocevar -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
[SLUG] hot swapping hard drives
I've just installed a sata hard drive bay for a second drive, the kind that has a little front door so you can slip the drive in and out. The point of installing it was to make it easy to change drives when doing backups, but I had assumed that I would have to shut down before taking the drive in or out. When I unmount it, Gnome announces that I can now remove the media, which surprised me a bit. Should I assume that this means I can safely hot swap this drive as long as it's unmounted? The nice man in the shop assured me that I needed all sorts of mobo magic to be able to do that, but of course he was talking Windows. I would hate to splat 500G of backup. Thanks, David. -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
[SLUG] May SLUG Monthly Meeting: Friday, May 29 2009
Hello SLUGgers! We are in need of speaking talent for our SLUG meetings. Our next meeting is on May 29 (announcement below), but we don't yet have an In Depth talk. If you have something that you'd like to talk about, let us know. This goes for any meeting, not just for the next one. You can generally assume that our meetings are on the last Friday of each month (barring December). For more information on speaking at SLUG, please see these resources: * http://www.slug.org.au/cfp.html http://www.slug.org.au/cfp.html * http://www.slug.org.au/meetings/guide.html http://www.slug.org.au/meetings/guide.html Thanks! == May SLUG Monthly Meeting == You can read the full version of this announcement on the Web at http://slug.org.au/node/114 When: 18.30 - 20.30, Friday, 29 May, 2009 We start at 18.30 but we ask that people arrive 15 minutes early so we can all get into the building and start on time. Please do not arrive before 18.00, as it may hinder business activities for our host! Appropriate signage and directions will be posted on the building. Where: Atlassian[0], 173-185 Sussex Street, Sydney (corner of Sussex and Market Street) Entry is via the rear on Slip Street. There are stairs going down along the outside of building from Sussex St to near the entrance. A map of the area and directions can be found here[1]. = Talks = ** General Talk ** James Purser: Thinkubating, Or How Local Government Learnt To Love Plone Some time ago I was approached to put together a quick and easy to use collaboration platform. I examined the options and Plone filled all the requirements. In this talk I'll go through the reasons why and give a couple of examples of how I am using Plone to support Local Government. ** In-Depth Talk ** TBA ** SLUGlets ** General discussion and QA about Linux, free software and open source. = Meeting Schedule = See here[2] for an explanation of the segments. * 18.15: Open Doors * 18.30: Announcements, News, Introductions * 18.45: General Talk * 19.30: Intermission * 19.45: Split into two groups for: o In-Depth Talk o SLUGlets * 20.30: Dinner Dinner is at Golden Harbour Restaurant, in Chinatown. We will be having the $24 Banquet[3], but we will be collecting $25 per head for ease of accounting and to cover a tip. We will be taking numbers during the break to confirm the reservation size. If you have any particular dietary requirements (e.g. vegetarian), or if you would prefer to order separately, let us know beforehand. Dinner is a great way to socialise and learn in a relaxed atmosphere :) We hope to see you there! [0] http://www.atlassian.com [1] http://tinyurl.com/35fxes [2] http://www.slug.org.au/meetings/meetingformat http://www.slug.org.au/meetings/meetingformat [3] http://www.goldenharbour.com.au/specials.html http://www.goldenharbour.com.au/specials.html -- Harrison Conlin -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] recovering xfs
On Friday 15 May 2009 21:03:06 slug-requ...@slug.org.au wrote: Lessons learnt: - a journalling file system is bigger than what you see, 3Tb is really 3.3Tb when doing a direct copy. - Get lots of harddisk in the beginning. 750G drives really only give you 698G. It is annoying to be 300G short and have to go to the shop again. - Expect lots of wait time, hard errors on raid take a long time to give up. - Don't promise anything, expect it to fail. - LVM is really cool and well worth the time to rad up on it. I am now going to LVM my home system. I'm planning to do this as well. I was thinking back to Mary's backup post last year and thinking if I could do lvm snapshots with an external harddrive. Still a bit new to lvm though. I think you have to install the alternate ubuntu cd to get lvm right? (unless you are using the server install instead of the desktop). Terry Pratchett says the chance of a million to one event happening is 9 / 10. LVM is really kewl iff you do frequent (daily) backups. Otherwise we await your plainted cry about how you lost 100 zigabytes of unique photos ... james -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Last Word Re: [SLUG] FINALISED - HD ( 1920 x 1080) monitor and Linux - advice pls.
To all who replied thanks. As I stated in an earlier post I was on Meds at the time I originally posted. Seems that I mixed up the monitor deatails - confused re various models that I was investigating and what I eventually purchased. Purchased a BenQ G2400WD Specs at http://www.benq.com/products/specificationsPrinter.cfm?product=1323 Very happy with it anyway. Owen, the shop is GDWorld, Shop 4 252 Botany Rd Alexadria. Thanks to all again Bill -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] hot swapping hard drives
On Fri, May 15, 2009 at 11:58:14PM EST, david wrote: I've just installed a sata hard drive bay for a second drive, the kind that has a little front door so you can slip the drive in and out. The point of installing it was to make it easy to change drives when doing backups, but I had assumed that I would have to shut down before taking the drive in or out. When I unmount it, Gnome announces that I can now remove the media, which surprised me a bit. Should I assume that this means I can safely hot swap this drive as long as it's unmounted? The nice man in the shop assured me that I needed all sorts of mobo magic to be able to do that, but of course he was talking Windows. I would hate to splat 500G of backup. As far as I am aware, new SATA standards, such as AHCI, allow the hot plugging of drives/cables, in fact without AHCI, machines wouldn't be able to offer E-Sata ports. I would check the type of connection for the drive and the rack that you mount it in. Since its new, I'd say it will be SATA, however you will have to find out whether the rack itself supports hot-plugging of drives, due to how the power to the drive is managed, as well as whether the controller on the motherboard supports AHCI, and if so, whether its running in AHCI mode. I am no expert on this stuff, but this is from what I've read and done with my own drives via E-Sata ports. Hope this helps Luke -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] hot swapping hard drives
Luke Yelavich wrote: On Fri, May 15, 2009 at 11:58:14PM EST, david wrote: I've just installed a sata hard drive bay for a second drive, the kind that has a little front door so you can slip the drive in and out. The point of installing it was to make it easy to change drives when doing backups, but I had assumed that I would have to shut down before taking the drive in or out. When I unmount it, Gnome announces that I can now remove the media, which surprised me a bit. Should I assume that this means I can safely hot swap this drive as long as it's unmounted? The nice man in the shop assured me that I needed all sorts of mobo magic to be able to do that, but of course he was talking Windows. I would hate to splat 500G of backup. As far as I am aware, new SATA standards, such as AHCI, allow the hot plugging of drives/cables, in fact without AHCI, machines wouldn't be able to offer E-Sata ports. I would check the type of connection for the drive and the rack that you mount it in. Since its new, I'd say it will be SATA, however you will have to find out whether the rack itself supports hot-plugging of drives, due to how the power to the drive is managed, as well as whether the controller on the motherboard supports AHCI, and if so, whether its running in AHCI mode. It's certainly a SATA drive and connection. I don't know how to check if the drive bay or my system supports AHCI. It's a Vantec MRK-100ST-BK and the only info I can find says Device supports SATA I/II, internal interface SATA I/II requires Windows 98SE -- Vista, or MacOS, requires SATA equipped system. Nothing about AHCI. Nothing about hot swapping. Google gives me plenty of places to buy it, but no hard information. There is a vantec website but this product isn't listed, although a later model is listed :( While on the subject, Ubuntu used to have a convenient little applet that gave a list of installed hardware. It seems to have vanished. Does anyone know what it was called and whether it still exists? -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
[SLUG] hot swapping hard drives
Hi David. As long as the drive in un-mounted you can safely remove/insert a device. You just need to make sure the drive Power connections allow hot-swapping, but generally you will get away with it normally if you haven't such PSU plug h/w. Just be aware that your PSU will require better surge power - so if your current PSU is a bit iffy, it will probably fail in time has been my experience. Hope this helps. Cheers. Grahame From: david da...@kenpro.com.au Date: 15 May 2009 11:58:14 PM To: slug@slug.org.au Subject: [SLUG] hot swapping hard drives I've just installed a sata hard drive bay for a second drive, the kind that has a little front door so you can slip the drive in and out. The point of installing it was to make it easy to change drives when doing backups, but I had assumed that I would have to shut down before taking the drive in or out. When I unmount it, Gnome announces that I can now remove the media, which surprised me a bit. Should I assume that this means I can safely hot swap this drive as long as it's unmounted? The nice man in the shop assured me that I needed all sorts of mobo magic to be able to do that, but of course he was talking Windows. I would hate to splat 500G of backup. Thanks, -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] hot swapping hard drives
Uhm, I'm reasonably sure there's more to hot swap than the physical and electrical connections. I'd thus do a little more research on the topic (like reading the datasheet(s) for your motherboard and SATA chipset) to ensure that the hardware supports it. There also may be a requirement for you to manually tell the OS to detach and attach disk devices. Adrian On Sat, May 16, 2009, Grahame Kelly wrote: Hi David. As long as the drive in un-mounted you can safely remove/insert a device. You just need to make sure the drive Power connections allow hot-swapping, but generally you will get away with it normally if you haven't such PSU plug h/w. Just be aware that your PSU will require better surge power - so if your current PSU is a bit iffy, it will probably fail in time has been my experience. Hope this helps. Cheers. Grahame From: david da...@kenpro.com.au Date: 15 May 2009 11:58:14 PM To: slug@slug.org.au Subject: [SLUG] hot swapping hard drives I've just installed a sata hard drive bay for a second drive, the kind that has a little front door so you can slip the drive in and out. The point of installing it was to make it easy to change drives when doing backups, but I had assumed that I would have to shut down before taking the drive in or out. When I unmount it, Gnome announces that I can now remove the media, which surprised me a bit. Should I assume that this means I can safely hot swap this drive as long as it's unmounted? The nice man in the shop assured me that I needed all sorts of mobo magic to be able to do that, but of course he was talking Windows. I would hate to splat 500G of backup. Thanks, -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html -- - Xenion - http://www.xenion.com.au/ - VPS Hosting - Commercial Squid Support - - $25/pm entry-level VPSes w/ capped bandwidth charges available in WA - -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] hot swapping hard drives
Luke Yelavich them...@themuso.com writes: On Fri, May 15, 2009 at 11:58:14PM EST, david wrote: I've just installed a sata hard drive bay for a second drive, the kind that has a little front door so you can slip the drive in and out. The point of installing it was to make it easy to change drives when doing backups, but I had assumed that I would have to shut down before taking the drive in or out. When I unmount it, Gnome announces that I can now remove the media, which surprised me a bit. It probably shouldn't. Hot-swap is a standard SATA feature. Should I assume that this means I can safely hot swap this drive as long as it's unmounted? Almost certainly. The nice man in the shop assured me that I needed all sorts of mobo magic to be able to do that, but of course he was talking Windows. No, he was right: you do have to have a suitable motherboard (really, SATA controller in the chipset), as well as a suitable driver, and a suitable SATA enclosure. It sounds like you have the last, most modern SATA controllers are suitable for the first ... and the driver, well, are reasonable. I would hate to splat 500G of backup. As far as I am aware, new SATA standards, such as AHCI, allow the hot plugging of drives/cables, in fact without AHCI, machines wouldn't be able to offer E-Sata ports. That isn't quite right. AHCI had /driver/ support, and exposed enough hotplug information to the driver, that Linux got support for it early. Other hardware might be supported; see here: http://ata.wiki.kernel.org/index.php/SATA_hardware_features If you do have an AHCI controller then, yes, it should be hotplug suitable and just work(tm). Meanwhile, eSATA is just a wiring standard on top of stock SATA, more or less, so it doesn't have much to do with AHCI, or vice-versa. [...] I am no expert on this stuff, but this is from what I've read and done with my own drives via E-Sata ports. You were more or less on target. :) Regards, Daniel -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] recovering xfs
jam j...@tigger.ws writes: On Friday 15 May 2009 21:03:06 slug-requ...@slug.org.au wrote: Lessons learnt: - a journalling file system is bigger than what you see, 3Tb is really 3.3Tb when doing a direct copy. - Get lots of harddisk in the beginning. 750G drives really only give you 698G. It is annoying to be 300G short and have to go to the shop again. - Expect lots of wait time, hard errors on raid take a long time to give up. - Don't promise anything, expect it to fail. - LVM is really cool and well worth the time to rad up on it. I am now going to LVM my home system. I'm planning to do this as well. I was thinking back to Mary's backup post last year and thinking if I could do lvm snapshots with an external harddrive. LVM snapshots are useful for getting a consistent backup, but just copying the bits is necessary for a real one. You might snapshot, then use the snapshot as the source of your backup if you run a database server or something similar though... Still a bit new to lvm though. I think you have to install the alternate ubuntu cd to get lvm right? (unless you are using the server install instead of the desktop). IIRC you can get LVM, but not software RAID, from the Ubuntu graphical installer. The alternate installer can do all of the above. Terry Pratchett says the chance of a million to one event happening is 9/10. ...which is great for comedic effect, but not actually an expression of real statistics. Well, and a comment on the pretty awful ability of humans to accurately assess and rate risk. LVM is really kewl iff you do frequent (daily) backups. Otherwise we await your plainted cry about how you lost 100 zigabytes of unique photos ... So, can you actually support your claim that LVM is disastrously unreliable with some, you know, evidence? I am curious to know, you see, because I have tens of terabytes of data sitting on LVM[1] across a wide range of machines, scaling from single-disk workstations through software-RAID servers to serious bulk-storage systems with hardware RAID. We have ... well. It probably suffices to say that we would notice fairly quickly if LVM was, in fact, unreliable. Regards, Daniel Besides, no one here is stupid enough to have their systems running *without* a daily backup, and without routinely checking it, right? Footnotes: [1] ...and XFS, to introduce the other technology that people love to make grandiose claims about the data-destroying abilities of. -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] hot swapping hard drives
Hi Adrian, David Slug list. Of the seven systems I look after, three have hot-swapping HDA's via a RAID5/6 drive enclosures, two systems have add-on SATAII caddies for hot-swap and the others are without hot-swapping. If your interested, and to reset your angst a little, I have been in the computing/engineering industry for 25++ years. On the software level the OS only has to ensure that all dirty (written too) memory pages are written out to the drives and such buffering flushed, drive index tables updated and written ALL before the drive is removed. The CLI command umount does this within the Linux / Unix OS. The sync command/programming API call is another way to do this programmatically. That is all that is required. On the hardware side, the PSU socket must ensure that power is presented to the drive before logic is connected (ground first). This is why the +12v, +5v and GND pins are usually extended about 8mm before the rest of the pins are connected. On the logic side, logic ground is the mandatory the first pin-out that is connected, together with any design reset or set pins. Additionally, the ability of the PSU to cope with demanding surges especially on +12v, +5V lines is very important, as the switching regulator may be upset by such demands. Most people wouldn't know this - that is why I mention it. Of course, by all means - investigate and be satisfied your got all the facts, its your system that will have to cope with any hot- swapping PSU and logic levels. Cheers. Grahame On 16/05/2009, at 2:06 PM, Adrian Chadd wrote: Uhm, I'm reasonably sure there's more to hot swap than the physical and electrical connections. I'd thus do a little more research on the topic (like reading the datasheet(s) for your motherboard and SATA chipset) to ensure that the hardware supports it. There also may be a requirement for you to manually tell the OS to detach and attach disk devices. Adrian On Sat, May 16, 2009, Grahame Kelly wrote: Hi David. As long as the drive in un-mounted you can safely remove/insert a device. You just need to make sure the drive Power connections allow hot-swapping, but generally you will get away with it normally if you haven't such PSU plug h/w. Just be aware that your PSU will require better surge power - so if your current PSU is a bit iffy, it will probably fail in time has been my experience. Hope this helps. Cheers. Grahame From: david da...@kenpro.com.au Date: 15 May 2009 11:58:14 PM To: slug@slug.org.au Subject: [SLUG] hot swapping hard drives I've just installed a sata hard drive bay for a second drive, the kind that has a little front door so you can slip the drive in and out. The point of installing it was to make it easy to change drives when doing backups, but I had assumed that I would have to shut down before taking the drive in or out. When I unmount it, Gnome announces that I can now remove the media, which surprised me a bit. Should I assume that this means I can safely hot swap this drive as long as it's unmounted? The nice man in the shop assured me that I needed all sorts of mobo magic to be able to do that, but of course he was talking Windows. I would hate to splat 500G of backup. Thanks, -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html -- - Xenion - http://www.xenion.com.au/ - VPS Hosting - Commercial Squid Support - - $25/pm entry-level VPSes w/ capped bandwidth charges available in WA - -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
