* re: [linux-lvm] EVMS @ 2002-08-27 15:39 ` Greg Freemyer 2002-08-27 15:46 ` Paul Lussier 0 siblings, 1 reply; 12+ messages in thread From: Greg Freemyer @ 2002-08-27 15:39 UTC (permalink / raw) To: LVM Mailing list I know that the latest xfs release (March) does not support EVMS with RAID 5 sets. There may be other problems with the pairing as well. Both the EVMS and XFS teams are working to get this supported in the next release. (That looks to be a couple of months away.) >> Hi all, >> I stumbled across something from IBM called EVMS today and was >> wondering if anyone had used it, and if so, what they thought of it? >> How does it differ from LVM? >> Here's the URL: >> http://oss.software.ibm.com/developerworks/opensource/evms >> It appears to be open source and is on Sourceforge as well. >> Thanks for any comments, >> -- >> Seeya, >> Paul >> -- >> It may look like I'm just sitting here doing nothing, >> but I'm really actively waiting for all my problems to go away. >> If you're not having fun, you're not doing it right! >> _______________________________________________ >> linux-lvm mailing list >> linux-lvm@sistina.com >> http://lists.sistina.com/mailman/listinfo/linux-lvm >> read the LVM HOW-TO at http://www.sistina.com/lvm/Pages/howto.html Greg Freemyer Internet Engineer Deployment and Integration Specialist Compaq ASE - Tru64 v4, v5 Compaq Master ASE - SAN Architect The Norcross Group www.NorcrossGroup.com ^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [linux-lvm] EVMS 2002-08-27 15:39 ` [linux-lvm] EVMS Greg Freemyer @ 2002-08-27 15:46 ` Paul Lussier 0 siblings, 0 replies; 12+ messages in thread From: Paul Lussier @ 2002-08-27 15:46 UTC (permalink / raw) To: linux-lvm In a message dated: Tue, 27 Aug 2002 16:34:49 EDT Greg Freemyer said: >I know that the latest xfs release (March) does not support EVMS with RAID 5 = >sets. > >There may be other problems with the pairing as well. > >Both the EVMS and XFS teams are working to get this supported in the next = >release. (That looks to be a couple of months away.) Well, currently I'm not using XFS, I'm mucking around with ext3 and ReiserFS. Though it's good to know XFS isn't an option right now (I did like XFS back when I was playing with it, and will probably go back that way sometime :) Thanks! -- Seeya, Paul -- It may look like I'm just sitting here doing nothing, but I'm really actively waiting for all my problems to go away. If you're not having fun, you're not doing it right! ^ permalink raw reply [flat|nested] 12+ messages in thread
* re: [linux-lvm] Re: LVM writes on raw disk of ATA RAID Mirror @ 2003-04-29 17:01 ` Greg Freemyer 2003-04-29 17:41 ` Ewen McNeill 0 siblings, 1 reply; 12+ messages in thread From: Greg Freemyer @ 2003-04-29 17:01 UTC (permalink / raw) To: LVM Mailing list >> Now y'all can tell me that the Promise ATA RAID cards suck and I >> shouldn't use them, and I should get a hardware RAID card, and so on >> (as I saw happened to the person who described this issue in October >> 2002; see >> http://lists.sistina.com/pipermail/linux-lvm/2002-October/012508.html >> and >> http://lists.sistina.com/pipermail/linux-lvm/2002-October/012516.html). >> And I'll happily agree with you, but for two small facts: >> - the hardware RAID cards cost more than twice what the drives cost, and >> they're 120GB IDE drives with large caches; let alone SCSI hardware >> RAID (which also increases the cost of the disks a lot too); Just thought I would point out that a 2-channel 3ware card is about the price of a single 80GB drive. (i.e. $130 US) I love the 3-ware cards and they are not cost prohibitive in my opinion. My only problem is I wish the failure/rebuild process was more automated than it currently is. Obviously, LVM and MD should still work together regardless. Greg -- Greg Freemyer ^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [linux-lvm] Re: LVM writes on raw disk of ATA RAID Mirror 2003-04-29 17:01 ` [linux-lvm] Re: LVM writes on raw disk of ATA RAID Mirror Greg Freemyer @ 2003-04-29 17:41 ` Ewen McNeill 2003-04-29 18:13 ` Goetz Bock 0 siblings, 1 reply; 12+ messages in thread From: Ewen McNeill @ 2003-04-29 17:41 UTC (permalink / raw) To: linux-lvm In message <20030429220328.XULC259.imf39bis.bellsouth.net@tiger2>, Greg Freemyer writes: > >> Now y'all can tell me that the Promise ATA RAID cards suck and I > >> shouldn't use them, and I should get a hardware RAID card, [....] > >> And I'll happily agree with you, but for two small facts: > >> - the hardware RAID cards cost more than twice what the drives cost, and > >> they're 120GB IDE drives with large caches; let alone SCSI hardware > >> RAID (which also increases the cost of the disks a lot too); > >Just thought I would point out that a 2-channel 3ware card is about the price >of a single 80GB drive. (i.e. $130 US) Around here (New Zealand) I can buy a 120GB IDE disk, with a 3 year warrenty, and a 8MB cache, for that sort of price (NZ$280 -> US$140 ish). Still, that's a lot closer to the price of the Promise cards (I'd previously only seen the 3-ware cards with prices around the US$250 ish sort of mark). Is that for the 3Ware 7000-2 card, which appears to be a 2-drive (single IDE channel?), card as best I can tell? Or for the 3Ware 7500-4LP card which appears to be a 4-drive (2 IDE channel?) card? (The Promise TX2000, and most of the Promise on-board ata-raid chipsets, are 2 IDE channels, 4 drives max -- although of course for best performance you really only want one drive per IDE channel.) Now all I need to find is a source of 3ware IDE cards in New Zealand; I haven't found any retail sources so far, and the one distributor I found mentioned doesn't even have a website in New Zealand (it redirects to a flash-only overseas website). Thanks for the comments. >Obviously, LVM and MD should still work together regardless. FWIW, my problem is with LVM and ata-raid (as implemented by various Promise cards). I haven't been able to determine whether LVM and MD (Linux software RAID) will work together or not -- although based on what I found I'd be somewhat surprised if they do work together correctly, because it seems to be an accident rather than good design (the same vgscan rescan issues would seem to affect MD as affect software RAID, unless some lucky coincidence prevents the raw IDE channels being recognised). Perhaps making LVM and ataraid work together properly is "too hard" (although personally I think it can be done with merely an ugly kludge -- viz, scan the ataraid and md devices first). But IMHO either LVM and ataraid should work properly, or it should be really really obvious that they won't work together (eg, fails to initialise on ataraid devices, reports errors if you try, etc). The current situation of mentioning ataraid support, and then silently failing is very dangerous. Ewen ^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [linux-lvm] Re: LVM writes on raw disk of ATA RAID Mirror 2003-04-29 17:41 ` Ewen McNeill @ 2003-04-29 18:13 ` Goetz Bock 2003-04-29 18:23 ` Ewen McNeill 0 siblings, 1 reply; 12+ messages in thread From: Goetz Bock @ 2003-04-29 18:13 UTC (permalink / raw) To: linux-lvm On Wed, Apr 30 '03 at 10:42, Ewen McNeill wrote: > [ ... ] Is that for the 3Ware 7000-2 card, which appears to be > a 2-drive (single IDE channel?), [ ... ] most likely for the 7000-2 card, what can only do raid0/1 and threfor lakes the expensive raid5 engine. still i use it happily > >Obviously, LVM and MD should still work together regardless. > FWIW, my problem is with LVM and ata-raid [ ... ] > Perhaps making LVM and ataraid work together properly is "too hard" > [ ... ] > But IMHO either LVM and ataraid should work properly, or it should be > really really obvious that they won't work together during my last/first/only time i had to deal with ataraid, and IIRC, the promise IDE driver had a compile time flag where it would not touch initialised raid arrays. aktivating this flag would simply remove the offending disks from the list of ide disks and make it available via ataraid only. OTOH I might have had a too long day and my memory is all wrong. lukily I don't have to deal with this box any more ;-) and therefor can not check this. -- Goetz Bock (c) 2003 as blacknet.de - Munich - Germany /"\ IT Consultant GNU FDL 1.1 secure mobile Linux everNETting \ / X ASCII Ribbon Campaign against HTML email & microsoft attachments / \ ^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [linux-lvm] Re: LVM writes on raw disk of ATA RAID Mirror 2003-04-29 18:13 ` Goetz Bock @ 2003-04-29 18:23 ` Ewen McNeill 2003-04-29 19:30 ` Ewen McNeill 0 siblings, 1 reply; 12+ messages in thread From: Ewen McNeill @ 2003-04-29 18:23 UTC (permalink / raw) To: linux-lvm In message <20030430011344.N16789@zealot.blacknet.de>, Goetz Bock writes: >during my last/first/only time i had to deal with ataraid, and IIRC, >the promise IDE driver had a compile time flag where it would not touch >initialised raid arrays. >aktivating this flag would simply remove the offending disks from the >list of ide disks and make it available via ataraid only. It would be nice if it were possible to do this. Is this perhaps the CONFIG_PDC202XX_FORCE flag (turned off, or on)? The Linux kernel configure help for it isn't very enlightening. And as best I can tell it affects only the flags passed to some of the Promise cards during setup. But interestingly _not_ the PDC20271 which is on the Promise TX2000 card I have. (Or the PDC20268, PDC20269, PDC20275, or PDC20277. It does affect the PDC20270 and PDC20276 though, and most of the older PDC chipsets (in pdc202xx_old.h).) Ewen ^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [linux-lvm] Re: LVM writes on raw disk of ATA RAID Mirror 2003-04-29 18:23 ` Ewen McNeill @ 2003-04-29 19:30 ` Ewen McNeill 2003-04-30 12:35 ` Andrew Rechenberg 0 siblings, 1 reply; 12+ messages in thread From: Ewen McNeill @ 2003-04-29 19:30 UTC (permalink / raw) To: linux-lvm In message <20030429232352.DC21EAE4F5@basilica.la.naos.co.nz>, Ewen McNeill writes: >In message <20030430011344.N16789@zealot.blacknet.de>, Goetz Bock writes: >>during my last/first/only time i had to deal with ataraid, and IIRC, >>the promise IDE driver had a compile time flag where it would not touch >>initialised raid arrays. >>aktivating this flag would simply remove the offending disks from the >>list of ide disks and make it available via ataraid only. > >It would be nice if it were possible to do this. Is this perhaps the >CONFIG_PDC202XX_FORCE flag (turned off, or on)? According to this message: http://groups.google.com/groups?hl=en&lr=&ie=UTF-8&selm=20030405112008%2462da%40gated-at.bofh.it from Andre Hedrick (Linux IDE maintainer), the CONFIG_PDC202XX_FORCE option is intended to force recognition of the Promise card's IDE channels as IDE devices, in order to be able to use the Linux pdcraid (ATA-RAID) driver. (They are apparently semi-disabled in the PCI configuration data, by default, so that only the Promise SCSI device driver can find them.) It should be on for using the pdcraid/ata-raid support, and off if you are using the Promise "SCSI" device driver. (And as I noted earlier, only certain chipsets seem to actually use this option; the rest just default to forced on.) This tends to confirm my view that if you use the ataraid driver, then you'll see both the raw /dev/hd* devices, and also the /dev/ataraid/d0* devices, since the ataraid/pdcraid driver appears to search the /dev/hd* IDE controllers for likely devices based on partition signatures. Which means that LVM needs to deal with the aliasing effects in some manner, either by recognising the ataraid devices first and ignoring the underlying devices, or by very loudly refusing to work with ataraid at all. Ewen ^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [linux-lvm] Re: LVM writes on raw disk of ATA RAID Mirror 2003-04-29 19:30 ` Ewen McNeill @ 2003-04-30 12:35 ` Andrew Rechenberg 2003-04-30 14:31 ` Ewen McNeill 0 siblings, 1 reply; 12+ messages in thread From: Andrew Rechenberg @ 2003-04-30 12:35 UTC (permalink / raw) To: linux-lvm vgscan has similar problems with MD devices in a software RAID10 (but not RAID1) configuration. In software RAID10 one creates a number of software RAID1 devices and then stripes across those with RAID0. For example if you have a 4 disk RAID10 setup you would have /dev/md0 and /dev/md1 as RAID1 devices and then /dev/md2 would be a stripe across /dev/md[0,1] The problem occurs when vgcreate adds the LVM metadata to the device. When you run 'vgcreate somename0 /dev/md2' it adds the metadata to /dev/md2, but since /dev/md0 is the first device in the RAID10 array, the metadata is in the exact same location on /dev/md0 and /dev/md2. Upon reboot (or a subsequent vgscan), LVM complains that it can't find all of the PE's on the volume group created because it's reading the information from md0 instead of md2 I was trying to hack vgscan to get my setup working but I needed the box working ASAP so time dictated that I use the KludgeMethod(tm). Someone on the list recommended that I move /dev/md0 before I run my vgscan. That worked in my case and I hacked my sysint script to move md0, run vgscan, and then move it back. Not elegant AT ALL, but it works. I'm not sure if a similar quick fix could work for you or not. You would have to make sure that the ataraid driver "built" the /dev/ataraid* entries, then move /dev/hd* somewhere, run vgscan, and then move them back. Make sure you test first and have a backup (do people still do those? :) ) before trying anything. HTH, Andy. On Tue, 2003-04-29 at 20:30, Ewen McNeill wrote: > In message <20030429232352.DC21EAE4F5@basilica.la.naos.co.nz>, Ewen McNeill writes: > >In message <20030430011344.N16789@zealot.blacknet.de>, Goetz Bock writes: > >>during my last/first/only time i had to deal with ataraid, and IIRC, > >>the promise IDE driver had a compile time flag where it would not touch > >>initialised raid arrays. > >>aktivating this flag would simply remove the offending disks from the > >>list of ide disks and make it available via ataraid only. > > > >It would be nice if it were possible to do this. Is this perhaps the > >CONFIG_PDC202XX_FORCE flag (turned off, or on)? > > According to this message: > > http://groups.google.com/groups?hl=en&lr=&ie=UTF-8&selm=20030405112008%2462da%40gated-at.bofh.it > > from Andre Hedrick (Linux IDE maintainer), the CONFIG_PDC202XX_FORCE > option is intended to force recognition of the Promise card's IDE > channels as IDE devices, in order to be able to use the Linux pdcraid > (ATA-RAID) driver. (They are apparently semi-disabled in the PCI > configuration data, by default, so that only the Promise SCSI device > driver can find them.) It should be on for using the pdcraid/ata-raid > support, and off if you are using the Promise "SCSI" device driver. > (And as I noted earlier, only certain chipsets seem to actually use this > option; the rest just default to forced on.) > > This tends to confirm my view that if you use the ataraid driver, then > you'll see both the raw /dev/hd* devices, and also the /dev/ataraid/d0* > devices, since the ataraid/pdcraid driver appears to search the /dev/hd* > IDE controllers for likely devices based on partition signatures. > > Which means that LVM needs to deal with the aliasing effects in some > manner, either by recognising the ataraid devices first and ignoring the > underlying devices, or by very loudly refusing to work with ataraid at > all. > > Ewen > > _______________________________________________ > linux-lvm mailing list > linux-lvm@sistina.com > http://lists.sistina.com/mailman/listinfo/linux-lvm > read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/ ^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [linux-lvm] Re: LVM writes on raw disk of ATA RAID Mirror 2003-04-30 12:35 ` Andrew Rechenberg @ 2003-04-30 14:31 ` Ewen McNeill 2003-04-30 17:58 ` Alasdair G Kergon 2003-05-02 14:07 ` Andrew Rechenberg 0 siblings, 2 replies; 12+ messages in thread From: Ewen McNeill @ 2003-04-30 14:31 UTC (permalink / raw) To: linux-lvm In message <1051724087.19901.287.camel@cinshrlnxws01.shermfin.com>, Andrew Reche nberg writes: >>[LVM 1.0.x; vgscan finds parts of RAID arrays and uses those instead] >vgscan has similar problems with MD devices in a software RAID10 (but >not RAID1) configuration. [...] Interesting. I've been told, and found in the source, that there were some hacks in LVM to make LVM and md work in some common situations (basically there's a loop after the first device scan which tries to eliminate some of the duplicates; and there's a /* FIXME */ comment immediately before that loop). It seems that you've found one of the situations where these hacks are too limited. >I was trying to hack vgscan to get my setup working but I needed the box >working ASAP so time dictated that I use the KludgeMethod(tm). Someone >on the list recommended that I move /dev/md0 before I run my vgscan. >[....] That is really quite ugly :-) I suspect something like that might work for the ataraid case too, right up to the point that someone runs vgscan for some reason without going through the "hide things from vgscan so it doesn't get it wrong" ritual -- at which point (with a little prompting) it silently swaps over to using part of the RAID array, and the RAID array gets out of sync, and then on next reboot it swaps back to using the RAID array, and the partitions are corrupt. I'm afraid that's a little too much potential excitement for my liking! I've been told that LVM 2 has some support where you can say what devices to scan (and what devices not to scan). I've not looked at LVM 2 yet, so I don't know how fine grained it is, but it might suit your situation. However after all this investigation I can't help thinking that the LVM vgscan approach is broken by design, particularly to be run automatically on startup. The idea that one can somehow look through all the connected devices and guess which one to use, and then automatically use those guesses on the assumption they'll always be right, just seems to be asking for trouble. Static configuration files, and having these things under manual control, seems a far more reliable way to approach the situation. For now this ataraid system will be built without LVM, as it seems the only way to be sure that the RAID array will actually always be used. Thanks for your comments, Ewen ^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [linux-lvm] Re: LVM writes on raw disk of ATA RAID Mirror 2003-04-30 14:31 ` Ewen McNeill @ 2003-04-30 17:58 ` Alasdair G Kergon 2003-05-02 14:07 ` Andrew Rechenberg 1 sibling, 0 replies; 12+ messages in thread From: Alasdair G Kergon @ 2003-04-30 17:58 UTC (permalink / raw) To: linux-lvm On Thu, May 01, 2003 at 07:30:30AM +1200, Ewen McNeill wrote: > I've been told that LVM 2 has some support where you can say what > devices to scan (and what devices not to scan). LVM2 offers selection by device type (i.e. the names that appear in /proc/devices giving block device major numbers) and regular-expression based selection by device name. Alasdair -- agk@uk.sistina.com ^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [linux-lvm] Re: LVM writes on raw disk of ATA RAID Mirror 2003-04-30 14:31 ` Ewen McNeill 2003-04-30 17:58 ` Alasdair G Kergon @ 2003-05-02 14:07 ` Andrew Rechenberg 2003-05-02 15:19 ` [linux-lvm] LVM, GFS, and clustered mail servers Scott Parish 1 sibling, 1 reply; 12+ messages in thread From: Andrew Rechenberg @ 2003-05-02 14:07 UTC (permalink / raw) To: linux-lvm I forgot to mention that I move the md0 entry back into place after I run vgscan. It's worked quite well and across numerous reboots. It is VERY ugly, but it "Works For Me(TM)" :) On Wed, 2003-04-30 at 15:30, Ewen McNeill wrote: > In message <1051724087.19901.287.camel@cinshrlnxws01.shermfin.com>, Andrew Reche > nberg writes: > >>[LVM 1.0.x; vgscan finds parts of RAID arrays and uses those instead] > >vgscan has similar problems with MD devices in a software RAID10 (but > >not RAID1) configuration. [...] > > Interesting. I've been told, and found in the source, that there were > some hacks in LVM to make LVM and md work in some common situations > (basically there's a loop after the first device scan which tries to > eliminate some of the duplicates; and there's a /* FIXME */ comment > immediately before that loop). It seems that you've found one of > the situations where these hacks are too limited. > > >I was trying to hack vgscan to get my setup working but I needed the box > >working ASAP so time dictated that I use the KludgeMethod(tm). Someone > >on the list recommended that I move /dev/md0 before I run my vgscan. > >[....] > > That is really quite ugly :-) I suspect something like that might work > for the ataraid case too, right up to the point that someone runs vgscan > for some reason without going through the "hide things from vgscan so it > doesn't get it wrong" ritual -- at which point (with a little prompting) > it silently swaps over to using part of the RAID array, and the RAID > array gets out of sync, and then on next reboot it swaps back to using > the RAID array, and the partitions are corrupt. > > I'm afraid that's a little too much potential excitement for my liking! > > I've been told that LVM 2 has some support where you can say what > devices to scan (and what devices not to scan). I've not looked at LVM > 2 yet, so I don't know how fine grained it is, but it might suit your > situation. > > However after all this investigation I can't help thinking that the LVM > vgscan approach is broken by design, particularly to be run automatically > on startup. The idea that one can somehow look through all the connected > devices and guess which one to use, and then automatically use those > guesses on the assumption they'll always be right, just seems to be asking > for trouble. Static configuration files, and having these things under > manual control, seems a far more reliable way to approach the situation. > > For now this ataraid system will be built without LVM, as it seems the > only way to be sure that the RAID array will actually always be used. > > Thanks for your comments, > > Ewen > > _______________________________________________ > linux-lvm mailing list > linux-lvm@sistina.com > http://lists.sistina.com/mailman/listinfo/linux-lvm > read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/ -- Andrew Rechenberg <arechenberg@shermfin.com> Infrastrucutre Team, Sherman Financial Group ^ permalink raw reply [flat|nested] 12+ messages in thread
* [linux-lvm] LVM, GFS, and clustered mail servers 2003-05-02 14:07 ` Andrew Rechenberg @ 2003-05-02 15:19 ` Scott Parish 0 siblings, 0 replies; 12+ messages in thread From: Scott Parish @ 2003-05-02 15:19 UTC (permalink / raw) To: linux-lvm This is a little off the typical discussion found on the list, and I apologize in advance for the slight interruption. I'm looking for anyone who has used LVM and Sistina's GFS to implement a clustered mail server environment using commodity PCs. I use the term cluster here, somewhat loosely, to describe multiple machines providing the same or similar service(s), in this case mail services (pop, imap, webmail, smtp). I'm particularly interested in your use of LVM/GFS in implementing a shared mail store/filesystem. If you have such a setup, and could spare a few moments, I'd like to pick your brain on your cluster configuration and experiences. Feel free to reply to the list or directly. Some of the things I'd like to know are: Describe your config, number of machines, adapters, disk subsystems (manufacturer would be helpful for adapters and disk subsystem). Software you're using to provide mail services? (sendmail, qmail, cyrus, courier, squirrelmail, etc.) How many users do you serve? How did you decide to distribute workload? RR DNS? Split services among machines? Linux Virtual Server? Something else? Do you share more than the mail filesystem among machines? If so, what? Do you have any performance numbers? What snags did you hit? If you had to implement again, which would you choose: "big box" or the cluster? Anything else you'd like to volunteer. Thanks in advance, Scott -- Scott Parish, Systems Administrator, Pittsburg State University Thinking is the hardest work there is, which is probably the reason why so few engage in it. - Henry Ford ^ permalink raw reply [flat|nested] 12+ messages in thread
end of thread, other threads:[~2003-05-02 15:19 UTC | newest]
Thread overview: 12+ messages (download: mbox.gz follow: Atom feed
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[not found] <freemyer@NorcrossGroup.com>
2002-08-27 15:39 ` [linux-lvm] EVMS Greg Freemyer
2002-08-27 15:46 ` Paul Lussier
2003-04-29 17:01 ` [linux-lvm] Re: LVM writes on raw disk of ATA RAID Mirror Greg Freemyer
2003-04-29 17:41 ` Ewen McNeill
2003-04-29 18:13 ` Goetz Bock
2003-04-29 18:23 ` Ewen McNeill
2003-04-29 19:30 ` Ewen McNeill
2003-04-30 12:35 ` Andrew Rechenberg
2003-04-30 14:31 ` Ewen McNeill
2003-04-30 17:58 ` Alasdair G Kergon
2003-05-02 14:07 ` Andrew Rechenberg
2003-05-02 15:19 ` [linux-lvm] LVM, GFS, and clustered mail servers Scott Parish
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