Re: LVM *was* Re: [mythtv-users] Highest number of simultaneous streams recorded?
On Fri, Oct 14, 2005 at 03:45:16PM -0500, Alex Brekken wrote: If one wanted redundancy only (is that RAID-0??) then I take it you would skip LVM entirely, correct? - IOW, are the 2 mutually exclusive or can you use LVM with RAID? The reason I ask is because I'm starting to put together some plans to build a master backend server (currently I have a frontend/backend combo) which will not only house myth and it's recordings, but also all of my music and pictures/videos of the kids. (the latter of which I would want the redundancy in case of a drive failure). Raid 0 is striping for performance but no redundancy. Any other raid level (2,3,4,5,10) does redundancy. LVM basically gives you virtual partitions on top of anything that's set as an LVM partition type via fdisk. Some people use LVM ontop of raid. Someone may do raid 5 for redunancy and use LVM on top to allow them to shrink and grow virtual partitions as they want to move space around for mount points, but still have redunancy (Since LVM doesn't do redundancy). The only thing like raid LVM does is striping - but you can't resize a striped LVM partion, so LVM striping and Raid 0 are somewhat alike. --Brandon ___ mythtv-users mailing list mythtv-users@mythtv.org http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
Re: LVM *was* Re: [mythtv-users] Highest number of simultaneous streams recorded?
Thanks Brandon, that makes sense. For a masterbackend server that will probably have at most 2 clients, I don't get the feeling that striping the drives is necessary from a performance standpoint. I'm still trying to decide how to tackle the redundancy/backup issue. I'm wondering if doing this via RAID is overkill Rather than introduce that complication maybe I should just manually back the drives up every so often. On 10/17/05, Brandon Beattie [EMAIL PROTECTED] wrote:On Fri, Oct 14, 2005 at 03:45:16PM -0500, Alex Brekken wrote: If one wanted redundancy only (is that RAID-0??) then I take it you would skip LVM entirely, correct? - IOW, are the 2 mutually exclusive or can you use LVM with RAID? The reason I ask is because I'm starting to put together some plans to build a master backend server (currently I have a frontend/backend combo) which will not only house myth and it's recordings, but also all of my music and pictures/videos of the kids. (the latter of which I would want the redundancy in case of a drive failure). Raid 0 is striping for performance but no redundancy.Any other raidlevel (2,3,4,5,10) does redundancy.LVM basically gives you virtualpartitions on top of anything that's set as an LVM partition type via fdisk.Some people use LVM ontop of raid.Someone may do raid 5 forredunancy and use LVM on top to allow them to shrink and grow virtualpartitions as they want to move space around for mount points, but still have redunancy (Since LVM doesn't do redundancy).The only thing likeraid LVM does is striping - but you can't resize a striped LVM partion,so LVM striping and Raid 0 are somewhat alike.--Brandon ___mythtv-users mailing listmythtv-users@mythtv.org http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users ___ mythtv-users mailing list mythtv-users@mythtv.org http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
Re: LVM *was* Re: [mythtv-users] Highest number of simultaneous streams recorded?
Alex Brekken wrote: Thanks Brandon, that makes sense. For a masterbackend server that will probably have at most 2 clients, I don't get the feeling that striping the drives is necessary from a performance standpoint. I'm still trying to decide how to tackle the redundancy/backup issue. I'm wondering if doing this via RAID is overkill Rather than introduce that complication maybe I should just manually back the drives up every so often. I go the manual route. I export my DB to another filesystem regularly and DVD+/-R the things I have archived in Divx under MythVideo (3-4 files per disk) and I don't really care much if I were to lose my recordings because it is just TV and the only thing I save long term is shows for the kids which can always be rerecorded. Implementing redundancy, raid levels, etc. in Linux seem more hastle than their worth when I can just back up what is important and live with losing the rest. Kevin ___ mythtv-users mailing list mythtv-users@mythtv.org http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
LVM *was* Re: [mythtv-users] Highest number of simultaneous streams recorded?
On Friday 14 October 2005 14:25, Alex Brekken wrote: Steve, is there any way to add an LVM on an up-and-running system, or must it be done during the OS install when partitioning the disk? (sorry, I don't mean to hijack this thread but I figured this would be a quick answer) Thanks! On 10/14/05, Steve Adeff [EMAIL PROTECTED] wrote: On Friday 14 October 2005 10:16, Brandon Beattie wrote: The current limitations on number of streams has to do with what hardware you choose to use. This includes tuner cards, hard drives, network cards, and CPU. I think it would still be rather easy to get 10+ streams recording and 4-5 being played back (1 local, 3-4 remote) before you see any problems. To do this you would need either hardware assisted analog encoders, or an HD tuner because they won't use more than 3% or so CPU. To reach a 10Rec 5Play number, you would want a good processor and memory, something 3.4Ghz or over would be fine -- If you're not going to watch video locally though, I bet you could do all this with 2Ghz or less. Disk usage is the next issue. Using raid 0, 5 or 10 would help in this areas you may be able to do 15 streams total with 2-3 striped drives I would bet. Networking will be the final issue. HD streams run up to just under 20Mb/s. As much as we wish to get 1Gb/s speeds all the time, expecting much over 400Mb/s constant is not always possible. Myth struggles to play video smoothly unless it feels like it has room to breath and almost no packet loss. another option if you find yourself recording this much is to use LVM (logical volume manager). It would allow you to connect, say four 300gig drives and use them all as one AND stripe data across them (like RAID 0). Or you could use 3 striped and the 4th as a parity drive in case one dies. This would most definitely give you the drive speed required to not only record 4+ streams at once, but play back equally as many. Steve from my understanding, yes it is, and properly set up you can also add and remove drives from an LVM at any point as well. I recently discovered LVM so I've yet to implement it, but I did a good amount of research and it seems to be quite easy now and I did not see anything that made me think I'd have to reinstall. Of course, I wouldn't use a LVM for your root partition, at least until you know what your doing... I'm just going to be using it for my storage drives. Steve ___ mythtv-users mailing list mythtv-users@mythtv.org http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
Re: LVM *was* Re: [mythtv-users] Highest number of simultaneous streams recorded?
On Fri, Oct 14, 2005 at 03:11:42PM -0400, Steve Adeff wrote: another option if you find yourself recording this much is to use LVM (logical volume manager). It would allow you to connect, say four 300gig drives and use them all as one AND stripe data across them (like RAID 0). Or you could use 3 striped and the 4th as a parity drive in case one dies. This would most definitely give you the drive speed required to not only record 4+ streams at once, but play back equally as many. Steve from my understanding, yes it is, and properly set up you can also add and remove drives from an LVM at any point as well. I recently discovered LVM so I've yet to implement it, but I did a good amount of research and it seems to be quite easy now and I did not see anything that made me think I'd have to reinstall. Of course, I wouldn't use a LVM for your root partition, at least until you know what your doing... I'm just going to be using it for my storage drives. Before you go running off let me give you a warning. Although LVM supports striping, adding/removing disks, shrinking and growing fs's, they do _not_ all work together. If you stripe you can't add/remove disks or change fs size. If you use xfs or jfs you can't shrink a fs. After using Raid 0, 1, 5, LVM on 6 disks with XFS, JFS, and Reiser I have settled with only LVM and ReiserFS (As much as I dislike Reiser for performance downsides with many gig files compared to xfs and jfs). In my experience, raid 5 is overkill for my desire to record TV shows. Anything I want safe I backup to another computer completely. In dealing with 6 drives I've found it very useful to shrink fs's at times, and since ReiserFS (Not Reiser 4) is the only fs that supports shrinking I use it. Striping would be nice, but adding/removing disks I've found to be a much better feature. I've also found seagate drives to run 10%-30% faster for reading and writing (reading and writing 100+ gig files) plus the 5yr warranty comes in nice, since of 9 drives I've had in the last 3 years, half the Maxtor 200GB drives have gone bad. ___ mythtv-users mailing list mythtv-users@mythtv.org http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
Re: LVM *was* Re: [mythtv-users] Highest number of simultaneous streams recorded?
On Friday 14 October 2005 16:13, Brandon Beattie wrote: Before you go running off let me give you a warning. Although LVM supports striping, adding/removing disks, shrinking and growing fs's, they do _not_ all work together. If you stripe you can't add/remove disks or change fs size. If you use xfs or jfs you can't shrink a fs. After using Raid 0, 1, 5, LVM on 6 disks with XFS, JFS, and Reiser I have settled with only LVM and ReiserFS (As much as I dislike Reiser for performance downsides with many gig files compared to xfs and jfs). In my experience, raid 5 is overkill for my desire to record TV shows. Anything I want safe I backup to another computer completely. In dealing with 6 drives I've found it very useful to shrink fs's at times, and since ReiserFS (Not Reiser 4) is the only fs that supports shrinking I use it. Striping would be nice, but adding/removing disks I've found to be a much better feature. I've also found seagate drives to run 10%-30% faster for reading and writing (reading and writing 100+ gig files) plus the 5yr warranty comes in nice, since of 9 drives I've had in the last 3 years, half the Maxtor 200GB drives have gone bad. Thanks for the info! I'll keep all that in mind. I might just stick with a RAID 0 for my recording drive and leave backup to the LVM or plain filesystem or something... I'm looking at getting WD's w/ 3yr warranty's. I've had very good luck with them (and seagate as well) and they're about $40 less for 320gb than the seagates, which I can live with, since in 3 years time I plan on having 1TB drives ;-) (or something much larger than my current drives). ___ mythtv-users mailing list mythtv-users@mythtv.org http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
Re: LVM *was* Re: [mythtv-users] Highest number of simultaneous streams recorded?
If one wanted redundancy only (is that RAID-0??) then I take it you would skip LVM entirely, correct? - IOW, are the 2 mutually exclusive or can you use LVM with RAID? The reason I ask is because I'm starting to put together some plans to build a master backend server (currently I have a frontend/backend combo) which will not only house myth and it's recordings, but also all of my music and pictures/videos of the kids. (the latter of which I would want the redundancy in case of a drive failure). On 10/14/05, Steve Adeff [EMAIL PROTECTED] wrote: On Friday 14 October 2005 16:13, Brandon Beattie wrote: Before you go running off let me give you a warning.Although LVM supports striping, adding/removing disks, shrinking and growing fs's, they do _not_ all work together.If you stripe you can't add/remove disks or change fs size.If you use xfs or jfs you can't shrink a fs.After using Raid 0, 1, 5, LVM on 6 disks with XFS, JFS, and Reiser I have settled with only LVM and ReiserFS (As much as I dislike Reiser for performance downsides with many gig files compared to xfs and jfs). In my experience, raid 5 is overkill for my desire to record TV shows. Anything I want safe I backup to another computer completely.In dealing with 6 drives I've found it very useful to shrink fs's at times, and since ReiserFS (Not Reiser 4) is the only fs that supports shrinking I use it.Striping would be nice, but adding/removing disks I've found to be a much better feature. I've also found seagate drives to run 10%-30% faster for reading and writing (reading and writing 100+ gig files) plus the 5yr warranty comes in nice, since of 9 drives I've had in the last 3 years, half the Maxtor 200GB drives have gone bad.Thanks for the info!I'll keep all that in mind. I might just stick with a RAID 0 for my recordingdrive and leave backup to the LVM or plain filesystem or something... I'm looking at getting WD's w/ 3yr warranty's. I've had very good luck withthem (and seagate as well) and they're about $40 less for 320gb than theseagates, which I can live with, since in 3 years time I plan on having 1TB drives ;-) (or something much larger than my current drives).___mythtv-users mailing listmythtv-users@mythtv.org http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users ___ mythtv-users mailing list mythtv-users@mythtv.org http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
Re: LVM *was* Re: [mythtv-users] Highest number of simultaneous streams recorded?
On Fri, 2005-10-14 at 14:13 -0600, Brandon Beattie wrote: ng and writing 100+ gig files) plus the 5yr warranty comes in nice, since of 9 drives I've had in the last 3 years, half the Maxtor 200GB drives have gone bad. I just want to second this. I have had two 160GB Maxtor drives die within a month of purchase. Maxtor used to be a reliable brand when disks were smaller, but my experiences with their larger drives have been bad and I won't ever buy another one. Got shafted on a rebate to boot )-: --Greg ___ mythtv-users mailing list mythtv-users@mythtv.org http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
Re: LVM *was* Re: [mythtv-users] Highest number of simultaneous streams recorded?
On Friday 14 October 2005 16:45, Alex Brekken wrote: If one wanted redundancy only (is that RAID-0??) then I take it you would skip LVM entirely, correct? - IOW, are the 2 mutually exclusive or can you use LVM with RAID? The reason I ask is because I'm starting to put together some plans to build a master backend server (currently I have a frontend/backend combo) which will not only house myth and it's recordings, but also all of my music and pictures/videos of the kids. (the latter of which I would want the redundancy in case of a drive failure). I'm doing something similar, I already have a file server, I plan on having a seperate MythTV computer with its own recording drives, but I plan on doing xvid encodes to my file server. RAID 0 is striped, RAID 1 is mirroring. I want to basically have one large drive on the file server with some sort of parity backup in case I loose one of the drives. I'm hoping to do this with LVM and one drive for parity repair. Steve ___ mythtv-users mailing list mythtv-users@mythtv.org http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
