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Re: [Wlug] Meeting topics

by Jeff Moyer

Chuck Anderson <cra(a)WPI.EDU> writes: > On Sun, Feb 28, 2010 at 06:26:31PM -0500, Jeff Moyer wrote: >> If anyone is interested in a talk on SSDs, chime in. I can present my >> experiences with these devices. I've evaluated the performance of >> several vendors' products, ranging from the poor to the exemplary. I >> can talk about the modifications made in the block layer to accommodate >> for these devices, and the current implementation of the block discard >> support (which maps to ATA TRIM, which is important for device lognevity >> and performance) and how that is wired up to file systems such as ext4. > > I'm interested. I was considering using SSDs for my boot drive. Is > RAID protection necessary/advisable using SSDs? The answer is, as always, it depends. I'll cover this in more depth when I give the talk, but any RAID algorithm that needs to initialize every block of the device is going to hurt performance on SSDs. There is some question about the durability/reliability of the drives, and some of those concerns are valid, others aren't. If you are diligent about backups, or if the disk just holds the OS, I wouldn't worry too much about RAID. HTH, Jeff

March 1, 2010

Re: [Wlug] Meeting topics

by Jim Dibb

But then again, you didn't state how important your uptime of your system is. Sorry for leaving that bit out.... On Mon, Mar 1, 2010 at 4:45 PM, Jim Dibb <jimdibb(a)gmail.com> wrote: > > > On Mon, Mar 1, 2010 at 4:21 PM, Chuck Anderson <cra(a)wpi.edu> wrote: > >> >> >> I'm interested. I was considering using SSDs for my boot drive. Is >> RAID protection necessary/advisable using SSDs? >> _______________________________________________ >> Wlug mailing list >> Wlug(a)mail.wlug.org >> http://mail.wlug.org/mailman/listinfo/wlug >> > > SSDs have much higher reliability than HDD. > Mirroring is the only RAID level that does not impose a write penalty. > Mirroring SSDs is expensive > > Based on these 3 points, I'd say a backup is a much better solution than > RAID, unless you want to (R)AID-0 them into a stripe for even more insane > performance. > >

March 1, 2010

Re: [Wlug] Meeting topics

by Jim Dibb

On Mon, Mar 1, 2010 at 4:21 PM, Chuck Anderson <cra(a)wpi.edu> wrote: > > > I'm interested. I was considering using SSDs for my boot drive. Is > RAID protection necessary/advisable using SSDs? > _______________________________________________ > Wlug mailing list > Wlug(a)mail.wlug.org > http://mail.wlug.org/mailman/listinfo/wlug > SSDs have much higher reliability than HDD. Mirroring is the only RAID level that does not impose a write penalty. Mirroring SSDs is expensive Based on these 3 points, I'd say a backup is a much better solution than RAID, unless you want to (R)AID-0 them into a stripe for even more insane performance.

March 1, 2010

Re: [Wlug] Meeting topics

by Patrick Dignan

On 03/01/2010 04:21 PM, Chuck Anderson wrote: > On Sun, Feb 28, 2010 at 06:26:31PM -0500, Jeff Moyer wrote: > >> If anyone is interested in a talk on SSDs, chime in. I can present my >> experiences with these devices. I've evaluated the performance of >> several vendors' products, ranging from the poor to the exemplary. I >> can talk about the modifications made in the block layer to accommodate >> for these devices, and the current implementation of the block discard >> support (which maps to ATA TRIM, which is important for device lognevity >> and performance) and how that is wired up to file systems such as ext4. >> > I'm interested. I was considering using SSDs for my boot drive. Is > RAID protection necessary/advisable using SSDs? > _______________________________________________ > Wlug mailing list > Wlug(a)mail.wlug.org > http://mail.wlug.org/mailman/listinfo/wlug > I second Chuck here.

March 1, 2010

Re: [Wlug] Meeting topics

by Chuck Anderson

On Sun, Feb 28, 2010 at 06:26:31PM -0500, Jeff Moyer wrote: > If anyone is interested in a talk on SSDs, chime in. I can present my > experiences with these devices. I've evaluated the performance of > several vendors' products, ranging from the poor to the exemplary. I > can talk about the modifications made in the block layer to accommodate > for these devices, and the current implementation of the block discard > support (which maps to ATA TRIM, which is important for device lognevity > and performance) and how that is wired up to file systems such as ext4. I'm interested. I was considering using SSDs for my boot drive. Is RAID protection necessary/advisable using SSDs?

March 1, 2010

Re: [Wlug] Meeting topics

by Frank Sweetser

On 02/28/2010 06:26 PM, Jeff Moyer wrote: > If anyone is interested in a talk on SSDs, chime in. I can present my > experiences with these devices. I've evaluated the performance of > several vendors' products, ranging from the poor to the exemplary. I > can talk about the modifications made in the block layer to accommodate > for these devices, and the current implementation of the block discard > support (which maps to ATA TRIM, which is important for device lognevity > and performance) and how that is wired up to file systems such as ext4. Sounds like a good talk to me. -- Frank Sweetser fs at wpi.edu | For every problem, there is a solution that WPI Senior Network Engineer | is simple, elegant, and wrong. - HL Mencken GPG fingerprint = 6174 1257 129E 0D21 D8D4 E8A3 8E39 29E3 E2E8 8CEC

March 1, 2010

Re: [Wlug] Meeting topics

by Jeff Moyer

Frank Sweetser <fs(a)WPI.EDU> writes: > I've noticed that not too many people have putting in meeting topic requests, > so I thought that if anyone's interested I'd volunteer to throw together some > slides on BtrFS. > > For those of you who haven't heard of it, BtrFS is the next generation linux > filesystem. Though still in heavy development, it was included in the > mainstream kernel last year. It promises to scale to filesystems well beyond > what any of the current offerings can handle (including ext4), as well as > offering far greater flexibility and better data security for data admins. > > If you have anything else that you'd like to hear about, either instead of or > in addition to BtrFS, chime in, and hopefully someone else on the list will be > able to make it happen! If anyone is interested in a talk on SSDs, chime in. I can present my experiences with these devices. I've evaluated the performance of several vendors' products, ranging from the poor to the exemplary. I can talk about the modifications made in the block layer to accommodate for these devices, and the current implementation of the block discard support (which maps to ATA TRIM, which is important for device lognevity and performance) and how that is wired up to file systems such as ext4. Cheers, Jeff

Feb. 28, 2010

Re: [Wlug] How do I change the UUID on an NTFS partition? [Solved]

by Randy Cole

Adam Gomes found the same correkt solution I did. Thanks Adam. I could not find a utility to change the UUID of an NTFS partition. So I edited the boot sector of the partition. ACHTUNG! Editing the boot sector can cause loss of data and severe tire damage! You have been warned. % blkid | grep ntfs The partition I want to change is /dev/sdb14. % dd if=/dev/sdb14 of=superblockSDB14 bs=512 count=1 you can use a random-number generator to synthesize new UUID. Or you can just change a couple of digits. edit Volume Serial Number aka "UUID" bytes 0x48 thru 0x4F (due to endian, the hex digits are both backwards and reversed!): % hexeditor superblockSDB14 % sudo dd of=/dev/sdb14 if=superblockSDB14 bs=512 count=1 Adam Gomes wrote: > Sorry for spamming the list. > > Randy, In case you are curious about what's in that NTFS superblock, > here's a great reference: > http://technet.microsoft.com/en-us/library/cc781134(WS.10).aspx > <http://technet.microsoft.com/en-us/library/cc781134%28WS.10%29.aspx> > > If you wanted instructions for editting that superblock, this is > probably the simplest way: > > dd if=/dev/sda# of=block bs=512 count=1 > ghexedit2 block (or what hex editor you like) > dd if=block of=/dev/sda# bs=512 count=1 > > You may also want to keep a copy of the original block, just in case > your modified block is not happy. > > The serial number is stored in the 8 bytes starting at offset 0x48. > > Here's an example from one of my own NTFS Super Blocks: > > adam@adam-laptop:~$ hd block > 00000000 eb 52 90 4e 54 46 53 20 20 20 20 00 02 08 00 00 |.R.NTFS > .....| > 00000010 00 00 00 00 00 f8 00 00 3f 00 ff 00 3f 00 00 00 > |........?...?...| > 00000020 00 00 00 00 80 00 80 00 24 97 ff 04 00 00 00 00 > |........$.......| > 00000030 00 00 0c 00 00 00 00 00 72 f9 4f 00 00 00 00 00 > |........r.O.....| > 00000040 f6 00 00 00 01 00 00 00 *69 28 05 50 64 05 50 3a* > |........*i(.Pd.P:*| > 00000050 00 00 00 00 fa 33 c0 8e d0 bc 00 7c fb b8 c0 07 > |.....3.....|....| > > If you had any more questions, I'll gladly take them off list, too. > > On Wed, Feb 24, 2010 at 2:48 PM, Adam Gomes <adam(a)unixgeek.net > <mailto:adam@unixgeek.net>> wrote: > > OR .... > > If you absolutely need to change the UUID, then you can always > alter the superblock of the partition. This is a little scarry, > though. The superblock is the first 512 bytes of the partition. > You can edit it in the hex editor and the NTFS volume serial > number should be in 0x48 to 0x4f. It's only 8 bytes long. Just > alter a byte or two in that region, and you should have a new UUID. > > This is NOT for the faint of heart, though. > > > On Wed, Feb 24, 2010 at 2:30 PM, Adam Gomes <adam(a)unixgeek.net > <mailto:adam@unixgeek.net>> wrote: > > ntfslabel /dev/sdaX LABELNAME > > and in /etc/rfstab change the /dev/sdaX or UUID= part of the > line to LABEL=LALBELNAME > > That should do the trick. You may need to install a new > package to get ntfslabel, in Ubuntu, that package is ntfsprogs. > > > On Wed, Feb 24, 2010 at 2:14 PM, Randy Cole > <randyokc(a)gmail.com <mailto:randyokc@gmail.com>> wrote: > > I've done this before but I can't remember how. Gparted > (actually > ntfsclone) duplicates the UUID, so I cannot mount them both! > _______________________________________________ > Wlug mailing list > Wlug(a)mail.wlug.org <mailto:Wlug@mail.wlug.org> > http://mail.wlug.org/mailman/listinfo/wlug > > > > > ------------------------------------------------------------------------ > > _______________________________________________ > Wlug mailing list > Wlug(a)mail.wlug.org > http://mail.wlug.org/mailman/listinfo/wlug >

Feb. 24, 2010

Re: [Wlug] How do I change the UUID on an NTFS partition?

by Adam Gomes

Sorry for spamming the list. Randy, In case you are curious about what's in that NTFS superblock, here's a great reference: http://technet.microsoft.com/en-us/library/cc781134(WS.10).aspx If you wanted instructions for editting that superblock, this is probably the simplest way: dd if=/dev/sda# of=block bs=512 count=1 ghexedit2 block (or what hex editor you like) dd if=block of=/dev/sda# bs=512 count=1 You may also want to keep a copy of the original block, just in case your modified block is not happy. The serial number is stored in the 8 bytes starting at offset 0x48. Here's an example from one of my own NTFS Super Blocks: adam@adam-laptop:~$ hd block 00000000 eb 52 90 4e 54 46 53 20 20 20 20 00 02 08 00 00 |.R.NTFS .....| 00000010 00 00 00 00 00 f8 00 00 3f 00 ff 00 3f 00 00 00 |........?...?...| 00000020 00 00 00 00 80 00 80 00 24 97 ff 04 00 00 00 00 |........$.......| 00000030 00 00 0c 00 00 00 00 00 72 f9 4f 00 00 00 00 00 |........r.O.....| 00000040 f6 00 00 00 01 00 00 00 *69 28 05 50 64 05 50 3a* |........* i(.Pd.P:*| 00000050 00 00 00 00 fa 33 c0 8e d0 bc 00 7c fb b8 c0 07 |.....3.....|....| If you had any more questions, I'll gladly take them off list, too. On Wed, Feb 24, 2010 at 2:48 PM, Adam Gomes <adam(a)unixgeek.net> wrote: > OR .... > > If you absolutely need to change the UUID, then you can always alter the > superblock of the partition. This is a little scarry, though. The superblock > is the first 512 bytes of the partition. You can edit it in the hex editor > and the NTFS volume serial number should be in 0x48 to 0x4f. It's only 8 > bytes long. Just alter a byte or two in that region, and you should have a > new UUID. > > This is NOT for the faint of heart, though. > > > On Wed, Feb 24, 2010 at 2:30 PM, Adam Gomes <adam(a)unixgeek.net> wrote: > >> ntfslabel /dev/sdaX LABELNAME >> >> and in /etc/rfstab change the /dev/sdaX or UUID= part of the line to >> LABEL=LALBELNAME >> >> That should do the trick. You may need to install a new package to get >> ntfslabel, in Ubuntu, that package is ntfsprogs. >> >> >> On Wed, Feb 24, 2010 at 2:14 PM, Randy Cole <randyokc(a)gmail.com> wrote: >> >>> I've done this before but I can't remember how. Gparted (actually >>> ntfsclone) duplicates the UUID, so I cannot mount them both! >>> _______________________________________________ >>> Wlug mailing list >>> Wlug(a)mail.wlug.org >>> http://mail.wlug.org/mailman/listinfo/wlug >>> >> >> >

Feb. 24, 2010

Re: [Wlug] How do I change the UUID on an NTFS partition?

by Adam Gomes

OR .... If you absolutely need to change the UUID, then you can always alter the superblock of the partition. This is a little scarry, though. The superblock is the first 512 bytes of the partition. You can edit it in the hex editor and the NTFS volume serial number should be in 0x48 to 0x4f. It's only 8 bytes long. Just alter a byte or two in that region, and you should have a new UUID. This is NOT for the faint of heart, though. On Wed, Feb 24, 2010 at 2:30 PM, Adam Gomes <adam(a)unixgeek.net> wrote: > ntfslabel /dev/sdaX LABELNAME > > and in /etc/rfstab change the /dev/sdaX or UUID= part of the line to > LABEL=LALBELNAME > > That should do the trick. You may need to install a new package to get > ntfslabel, in Ubuntu, that package is ntfsprogs. > > > On Wed, Feb 24, 2010 at 2:14 PM, Randy Cole <randyokc(a)gmail.com> wrote: > >> I've done this before but I can't remember how. Gparted (actually >> ntfsclone) duplicates the UUID, so I cannot mount them both! >> _______________________________________________ >> Wlug mailing list >> Wlug(a)mail.wlug.org >> http://mail.wlug.org/mailman/listinfo/wlug >> > >

Feb. 24, 2010