[SFS] mounting linux filesystem from local drives
Jed Walker
jedwa@comcast.net
Thu, 12 Jan 2017 21:04:11 -0700
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Yes, editing fstab while the system is running is fine, I=E2=80=99ve =
done that a ton. I was wondering about the xfs_admin command. If I have =
the time I=E2=80=99ll that command and see what happens (and reply). I =
just can=E2=80=99t afford to waste time fixing it since I have to get it =
to the DC Monday.
Yes, I like LVM for adding more space but the drive bays are full so I =
figured it wouldn=E2=80=99t be happening and we=E2=80=99ll hopefully =
move off to a storage device for more space later.
=20
I appreciate all the help, and thanks for the article on LVM and =
performance.
=20
From: Aaron Brown [mailto:aayore@gmail.com]=20
Sent: Thursday, January 12, 2017 7:03 PM
To: Jed Walker
Cc: 'sfs'
Subject: Re: [SFS] mounting linux filesystem from local drives
=20
It's definitely fine to edit the fstab while the drive is online. It =
*should* be fine to provide a label with the drive online, but if you've =
got stuff you can't lose I'd advise testing somewhere else or unmounting =
the drive first. I'm really not sure if FS labels show up under =
/dev/mapper/. I think the label applies to the base block device, so I =
don't think device mapper will pick it up and put it in /dev/mapper/. =
Let me know what you find out. :)
Also - There's really no downside to LVM. It doesn't impact storage =
performace =
(http://unix.stackexchange.com/questions/7122/does-lvm-impact-performance=
) and it gives you a bunch of options that you might want in the future. =
If you ever start to run out of space, you could add a second RAID =
volume and use LVM to concatenate them together. If space isn't an =
issue, then you've got room for snapshots. =20
Jed Walker wrote:
Thank you Aaron. It is being use now, so can I run that while it is=20
being used to give it a label, and then change the fstab and remount=20
later? Also, when you say a =E2=80=9Clabel=E2=80=9D does that mean it =
will show as=20
something like /dev/mapper/<label> ?
*From:*Aaron Brown [mailto:aayore@gmail.com]
*Sent:* Thursday, January 12, 2017 6:36 PM
*To:* Jed Walker
*Cc:* sfs
*Subject:* Re: [SFS] mounting linux filesystem from local drives
The local drives won't move around on you. They're not subjected to=20
the same dynamic mapping that's incurred when you use remote disks.=20
But if you're worried about it, you could mount by label. Just use=20
`xfs_admin -L my_data_disk /dev/sdb1` to label the partition and use=20
LABEL=3Dmy_data_disk in place of /dev/sdb1 your fstab.
-Aaron
*Jed Walker* <mailto:jedwa@comcast.net>
January 12, 2017 at 6:29 PM
I have a local disk (raid10) I mounted for storage in CentOS 7. From=20
reading I believe there is no reason to put LVM on top and I can just=20
partition and mount. So I figured I mount the filesystem directly on=20
the partition.
/etc/fstab, like:
/dev/sdb1 /mydata xfs defaults,noatime 0 0
This all worked fine and seems fine after reboot, but I got worried.=20
This is not something I=E2=80=99ve done before since my experience is =
with big=20
databases, thus I have only worked with mounting external LUNs from=20
storage devices. On those I always use multipath and udev to associate=20
them to the disks because the /dev/<dev> names can change on reboot.
Is this not true with local drives? i.e. will the local drives always=20
mount with the same name, thus my /etc/fstab above is valid?
Thank you for your help,
Jed
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vlink=3Dpurple><div class=3DWordSection1><p class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497=
D'>Yes, editing fstab while the system is running is fine, I=E2=80=99ve =
done that a ton. I was wondering about the xfs_admin command. If I have =
the time I=E2=80=99ll that command and see what happens (and reply). I =
just can=E2=80=99t afford to waste time fixing it since I have to get it =
to the DC Monday.<o:p></o:p></span></p><p class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497=
D'><br><br>Yes, I like LVM for adding more space but the drive bays are =
full so I figured it wouldn=E2=80=99t be happening and we=E2=80=99ll =
hopefully move off to a storage device for more space =
later.<o:p></o:p></span></p><p class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497=
D'><o:p> </o:p></span></p><p class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497=
D'>I appreciate all the help, and thanks for the article on LVM and =
performance.<o:p></o:p></span></p><p class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497=
D'><o:p> </o:p></span></p><div><div =
style=3D'border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in =
0in 0in'><p class=3DMsoNormal><b><span =
style=3D'font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span>=
</b><span style=3D'font-size:10.0pt;font-family:"Tahoma","sans-serif"'> =
Aaron Brown [mailto:aayore@gmail.com] <br><b>Sent:</b> Thursday, January =
12, 2017 7:03 PM<br><b>To:</b> Jed Walker<br><b>Cc:</b> =
'sfs'<br><b>Subject:</b> Re: [SFS] mounting linux filesystem from local =
drives<o:p></o:p></span></p></div></div><p =
class=3DMsoNormal><o:p> </o:p></p><p class=3DMsoNormal>It's =
definitely fine to edit the fstab while the drive is online. It =
*should* be fine to provide a label with the drive online, but if you've =
got stuff you can't lose I'd advise testing somewhere else or unmounting =
the drive first. I'm really not sure if FS labels show up under =
/dev/mapper/. I think the label applies to the base block device, =
so I don't think device mapper will pick it up and put it in =
/dev/mapper/. Let me know what you find out. :)<br><br>Also =
- There's really no downside to LVM. It doesn't impact storage =
performace (<a =
href=3D"http://unix.stackexchange.com/questions/7122/does-lvm-impact-perf=
ormance">http://unix.stackexchange.com/questions/7122/does-lvm-impact-per=
formance</a>) and it gives you a bunch of options that you might want in =
the future. If you ever start to run out of space, you could add a =
second RAID volume and use LVM to concatenate them together. If =
space isn't an issue, then you've got room for snapshots. =
<br><br>Jed Walker wrote:<br><br><o:p></o:p></p><p =
class=3DMsoNormal><br>Thank you Aaron. It is being use now, so can I run =
that while it is <br>being used to give it a label, and then change the =
fstab and remount <br>later? Also, when you say a =
=E2=80=9Clabel=E2=80=9D does that mean it will show as <br>something =
like /dev/mapper/<label> ?<br><br>*From:*Aaron Brown [<a =
href=3D"mailto:aayore@gmail.com">mailto:aayore@gmail.com</a>]<br>*Sent:* =
Thursday, January 12, 2017 6:36 PM<br>*To:* Jed Walker<br>*Cc:* =
sfs<br>*Subject:* Re: [SFS] mounting linux filesystem from local =
drives<br><br>The local drives won't move around on you. They're not =
subjected to <br>the same dynamic mapping that's incurred when you use =
remote disks. <br>But if you're worried about it, you could mount by =
label. Just use <br>`xfs_admin -L my_data_disk /dev/sdb1` to label the =
partition and use <br>LABEL=3Dmy_data_disk in place of /dev/sdb1 your =
fstab.<br><br>-Aaron<br><br><br>*Jed Walker* <<a =
href=3D"mailto:jedwa@comcast.net">mailto:jedwa@comcast.net</a>><br><br=
>January 12, 2017 at 6:29 PM<br><br>I have a local disk (raid10) I =
mounted for storage in CentOS 7. From <br>reading I believe there is no =
reason to put LVM on top and I can just <br>partition and mount. So I =
figured I mount the filesystem directly on <br>the =
partition.<br><br>/etc/fstab, like:<br><br>/dev/sdb1 /mydata xfs =
defaults,noatime 0 0<br><br>This all worked fine and seems fine after =
reboot, but I got worried. <br>This is not something I=E2=80=99ve done =
before since my experience is with big <br>databases, thus I have only =
worked with mounting external LUNs from <br>storage devices. On those I =
always use multipath and udev to associate <br>them to the disks because =
the /dev/<dev> names can change on reboot.<br><br><br>Is this not =
true with local drives? i.e. will the local drives always <br>mount with =
the same name, thus my /etc/fstab above is valid?<br><br>Thank you for =
your help,<br><br>Jed<o:p></o:p></p></div></body></html>
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