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File System for RAID-5

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james at booths

Jun 14, 2009, 7:30 PM

Post #1 of 47 (3627 views)
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File System for RAID-5

Having just had a near-death experience with my non-RAID LVM system
for Myth, I am about to convert everything to a RAID-5 setup (software
RAID) with LVM on top. Before I go ahead does anyone have any
recommendations on best choice of file system to use, given that it
will be within LVM on RAID-5? I was going to go with XFS, but that
cannot be shrunk, which (as I have found) can be very irritating when
trying to reorganise your disks in an LVM. I know there are a bunch of
hot new file systems out now, but I? wary of trying something new in
an a setup like this.

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criggie at criggie

Jun 14, 2009, 7:40 PM

Post #2 of 47 (3527 views)
Permalink

Re: File System for RAID-5 [In reply to]

Consider doing none of that.

Consider a RAID1 for your system drives, and all the other drives in a
mythtv storage group. Programs will be written to individual drives, and
if any one dies it will not take out the others.

If you raid5, then you loose a drive worth of storage, and remember its
only TV. Not your critical personal data.

I suggest jfs because it has predictable fsck/mount times. Something like
ext3 will someday jump at boot and demand a fsck taking hours and hours.

james [at] booths wrote:
> Having just had a near-death experience with my non-RAID LVM system
> for Myth, I am about to convert everything to a RAID-5 setup (software
> RAID) with LVM on top. Before I go ahead does anyone have any
> recommendations on best choice of file system to use, given that it
> will be within LVM on RAID-5? I was going to go with XFS, but that
> cannot be shrunk, which (as I have found) can be very irritating when
> trying to reorganise your disks in an LVM. I know there are a bunch of
> hot new file systems out now, but I? wary of trying something new in
> an a setup like this.

--
Criggie

http://criggie.dyndns.org/

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jonathan.hoskin at gmail

Jun 14, 2009, 7:41 PM

Post #3 of 47 (3528 views)
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Re: File System for RAID-5 [In reply to]

ext3 has always worked for me when not using xfs.

Also, if you have a bit more money to burn, why not consider RAID-10 over
RAID-5? RAID-5 comes from a time when disks were expensive and n+1
redundancy was a lot cheaper than n+n. Nowadays n+n on desktop drives is
cheap enough, and software RAID-10 is going to be way faster than RAID-5.

On Mon, Jun 15, 2009 at 2:30 PM, <james [at] booths> wrote:

> Having just had a near-death experience with my non-RAID LVM system
> for Myth, I am about to convert everything to a RAID-5 setup (software
> RAID) with LVM on top. Before I go ahead does anyone have any
> recommendations on best choice of file system to use, given that it
> will be within LVM on RAID-5? I was going to go with XFS, but that
> cannot be shrunk, which (as I have found) can be very irritating when
> trying to reorganise your disks in an LVM. I know there are a bunch of
> hot new file systems out now, but I? wary of trying something new in
> an a setup like this.
>
>
> _______________________________________________
> mythtvnz mailing list
> mythtvnz [at] lists
> http://lists.ourshack.com/mailman/listinfo/mythtvnz
> Archives http://www.gossamer-threads.com/lists/mythtv/mythtvnz/
>

hads at nice

Jun 14, 2009, 7:46 PM

Post #4 of 47 (3529 views)
Permalink

Re: File System for RAID-5 [In reply to]

On Mon, 2009-06-15 at 14:41 +1200, Jonathan Hoskin wrote:
> Also, if you have a bit more money to burn, why not consider RAID-10
> over RAID-5? RAID-5 comes from a time when disks were expensive and n
> +1 redundancy was a lot cheaper than n+n. Nowadays n+n on desktop
> drives is cheap enough, and software RAID-10 is going to be way faster
> than RAID-5.

One point is that you can easily add more disk to a RAID5, and it's fast
enough for most things.

Personally I use JFS mounted on RAID5, no LVM. Not for TV recordings
though, they are just on a single partition as I don't care about them.

Always remember, RAID is for uptime, backups are for data security.

hads
--
http://nicegear.co.nz
New Zealand's Open Source Hardware Supplier

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steve at greengecko

Jun 14, 2009, 7:46 PM

Post #5 of 47 (3529 views)
Permalink

Re: File System for RAID-5 [In reply to]

If you really do expect to be dynamically changing file system sizes in
the future, then I'd go reiserfs. Personally, I doubt that this is going
to happen, so I'd stick with good old ext3, unless you're going to have
thousands of files in a small number of directories... unlikely with a
myth box!

Personally, now that 1TB disks are now comfortably under $200 each, I
don't even bother with Raid 5 now, but use plain mirroring instead.

Actually, that's not exactly true... with the cost of GB switches I
actually use a dedicated FreeNAS box and RAID 0+1 to get the best of all
worlds and hide my data where burglars ($deity forbid!) won't find it.

Steve.

On Mon, 2009-06-15 at 14:30 +1200, james [at] booths wrote:
> Having just had a near-death experience with my non-RAID LVM system
> for Myth, I am about to convert everything to a RAID-5 setup (software
> RAID) with LVM on top. Before I go ahead does anyone have any
> recommendations on best choice of file system to use, given that it
> will be within LVM on RAID-5? I was going to go with XFS, but that
> cannot be shrunk, which (as I have found) can be very irritating when
> trying to reorganise your disks in an LVM. I know there are a bunch of
> hot new file systems out now, but I? wary of trying something new in
> an a setup like this.
>
>
> _______________________________________________
> mythtvnz mailing list
> mythtvnz [at] lists
> http://lists.ourshack.com/mailman/listinfo/mythtvnz
> Archives http://www.gossamer-threads.com/lists/mythtv/mythtvnz/
--
Steve Holdoway <steve [at] greengecko>
http://www.greengecko.co.nz
MSN: steve [at] greengecko

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stevehodge at gmail

Jun 14, 2009, 8:01 PM

Post #6 of 47 (3535 views)
Permalink

Re: File System for RAID-5 [In reply to]

On Mon, Jun 15, 2009 at 2:46 PM, steve <steve [at] greengecko> wrote:

> If you really do expect to be dynamically changing file system sizes in
> the future, then I'd go reiserfs. Personally, I doubt that this is going
> to happen, so I'd stick with good old ext3, unless you're going to have
> thousands of files in a small number of directories... unlikely with a
> myth box!

Why? Both xfs and jfs support extending filesystems and both of them are
generally considered to be more suitable for large files than reiserfs.
Neither of them suffer from the slow delete issue that ext3 has either
(though that has been worked around in Myth).

Cheers,
Steve

g8ecj at gilks

Jun 14, 2009, 8:53 PM

Post #7 of 47 (3527 views)
Permalink

Re: File System for RAID-5 [In reply to]

> Having just had a near-death experience with my non-RAID LVM system
> for Myth, I am about to convert everything to a RAID-5 setup (software
> RAID) with LVM on top. Before I go ahead does anyone have any
> recommendations on best choice of file system to use, given that it
> will be within LVM on RAID-5? I was going to go with XFS, but that
> cannot be shrunk, which (as I have found) can be very irritating when
> trying to reorganise your disks in an LVM. I know there are a bunch of
> hot new file systems out now, but I? wary of trying something new in
> an a setup like this.

Having just this last week built a replacement for my 6 year old server,
I've basically used the same scheme again.

Huge raid5 array (the definition of huge is now very different to what it
was 6 years ago!!), LVM2 over the top, recordings and video partitions
with jfs (large files but not many of them) and ext3 for all the other
partitions (email, music etc). The system disk is separate and gets
regular backups into an external device, most of the stuff on the raid
array is expendable but by using smartd and mdadm I get an email if
something starts to fail.

Interesting that the new box is 10 times faster, has 5 times as much disk,
4 times as much ram and consumes less than half as much power...

--
Robin Gilks

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james at booths

Jun 14, 2009, 9:31 PM

Post #8 of 47 (3531 views)
Permalink

Re: File System for RAID-5 [In reply to]

On Monday 15 June 2009 14:40:46 Criggie wrote:
> Consider doing none of that.
>
> Consider a RAID1 for your system drives, and all the other drives in a
> mythtv storage group. Programs will be written to individual drives, and
> if any one dies it will not take out the others.
>
> If you raid5, then you loose a drive worth of storage, and remember its
> only TV. Not your critical personal data.
>
> I suggest jfs because it has predictable fsck/mount times. Something like
> ext3 will someday jump at boot and demand a fsck taking hours and hours.
>
> james [at] booths wrote:
> > Having just had a near-death experience with my non-RAID LVM system
> > for Myth, I am about to convert everything to a RAID-5 setup (software
> > RAID) with LVM on top. Before I go ahead does anyone have any
> > recommendations on best choice of file system to use, given that it
> > will be within LVM on RAID-5? I was going to go with XFS, but that
> > cannot be shrunk, which (as I have found) can be very irritating when
> > trying to reorganise your disks in an LVM. I know there are a bunch of
> > hot new file systems out now, but I? wary of trying something new in
> > an a setup like this.

I'm really not worried about TV recordings - it's my MASSIVE DVD library I am
more concerned about. I find LVM really convenient because I can just keep
adding on as the library grows (my RAID system will be 80% full from the
start, so another 1.5TB drive coming up....)

james at booths

Jun 14, 2009, 9:33 PM

Post #9 of 47 (3535 views)
Permalink

Re: File System for RAID-5 [In reply to]

On Monday 15 June 2009 14:46:07 Hadley Rich wrote:
> On Mon, 2009-06-15 at 14:41 +1200, Jonathan Hoskin wrote:
> > Also, if you have a bit more money to burn, why not consider RAID-10
> > over RAID-5? RAID-5 comes from a time when disks were expensive and n
> > +1 redundancy was a lot cheaper than n+n. Nowadays n+n on desktop
> > drives is cheap enough, and software RAID-10 is going to be way faster
> > than RAID-5.
>
> One point is that you can easily add more disk to a RAID5, and it's fast
> enough for most things.
>
> Personally I use JFS mounted on RAID5, no LVM. Not for TV recordings
> though, they are just on a single partition as I don't care about them.
>
> Always remember, RAID is for uptime, backups are for data security.
>
> hads

Wise words, but backing up 3TB+ of DVD's starts to get onerous.... At least
RAID gives me some security against disk failure (theft and fire are up to the
gods)

hads at nice

Jun 14, 2009, 9:47 PM

Post #10 of 47 (3534 views)
Permalink

Re: File System for RAID-5 [In reply to]

On Mon, 2009-06-15 at 16:33 +1200, James Booth wrote:
> Wise words, but backing up 3TB+ of DVD's starts to get onerous.... At
> least RAID gives me some security against disk failure (theft and fire
> are up to the gods)

Yeah I hear you. I currently have a 1TB drive for backups. It needs to
be upgraded to a 2TB drive and I'll still need to pick and choose what
media I backup.

hads
--
http://nicegear.co.nz
New Zealand's Open Source Hardware Supplier

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steve at greengecko

Jun 14, 2009, 9:48 PM

Post #11 of 47 (3529 views)
Permalink

Re: File System for RAID-5 [In reply to]

On Mon, 2009-06-15 at 16:33 +1200, James Booth wrote:

>
> Wise words, but backing up 3TB+ of DVD's starts to get onerous.... At
> least RAID gives me some security against disk failure (theft and fire
> are up to the gods)
Saturating a dedicated GBit network -> best part of 4 days. I think that
with those volumes and no mega budget, then a mirror/rsync solution is
the only feasible solution!

Of course, you *do* have the originals to store offsite (:

Steve
--
Steve Holdoway <steve [at] greengecko>
http://www.greengecko.co.nz
MSN: steve [at] greengecko

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james at booths

Jun 14, 2009, 10:06 PM

Post #12 of 47 (3529 views)
Permalink

Re: File System for RAID-5 [In reply to]

On Monday 15 June 2009 16:48:26 steve wrote:
> On Mon, 2009-06-15 at 16:33 +1200, James Booth wrote:
> > Wise words, but backing up 3TB+ of DVD's starts to get onerous.... At
> > least RAID gives me some security against disk failure (theft and fire
> > are up to the gods)
>
> Saturating a dedicated GBit network -> best part of 4 days. I think that
> with those volumes and no mega budget, then a mirror/rsync solution is
> the only feasible solution!
>
> Of course, you *do* have the originals to store offsite (:
>
> Steve

Actually, I do (for about 95% of them, anyway). The thought of having to re-
rip all those discs.....shudder.

mythtv at objectivity

Jun 15, 2009, 1:16 AM

Post #13 of 47 (3523 views)
Permalink

Re: File System for RAID-5 [In reply to]

Umm, no with raid 5, you lose a drive not the data. add a new drive
"rebuild" the set and continue as normal...

I have three 500GB drives in a raid-5 set. The server is a myth back-end
and a file server (and mysql server) also so I care about the data.
Frankly I don't care that much about the TV recordings (though I am
happy about the side affect of uptime the raid set gives) but having
down time would cause problems with WAF!

For a file system I have just used plain old ext3.

Criggie wrote:
> If you raid5, then you loose a drive worth of storage, and remember its
> only TV. Not your critical personal data.
>
>

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criggie at criggie

Jun 15, 2009, 1:30 AM

Post #14 of 47 (3530 views)
Permalink

Re: File System for RAID-5 [In reply to]

Umm... read it again. If you use a raid5 you will lose one disk worth of
storage space.

Four 1TB drives in a raid5 is 3TB.
Four 1TB drives in storage groups is 4TB.

Karl Leaning wrote:
> Umm, no with raid 5, you lose a drive not the data. add a new drive
> "rebuild" the set and continue as normal...

> Criggie wrote:
>> If you raid5, then you lose a drive worth of storage, and remember its
>> only TV. Not your critical personal data.

--
Criggie

http://criggie.dyndns.org/

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mythtv at objectivity

Jun 15, 2009, 1:40 AM

Post #15 of 47 (3522 views)
Permalink

Re: File System for RAID-5 [In reply to]

Not enough caffeine...

Criggie wrote:

Umm... read it again. If you use a raid5 you will lose one disk worth of storage space. Four 1TB drives in a raid5 is 3TB. Four 1TB drives in storage groups is 4TB. Karl Leaning wrote:
Umm, no with raid 5, you lose a drive not the data. add a new drive "rebuild" the set and continue as normal...

Criggie wrote:
If you raid5, then you lose a drive worth of storage, and remember its only TV. Not your critical personal data.

jim at inode

Jun 15, 2009, 2:29 AM

Post #16 of 47 (3530 views)
Permalink

Re: File System for RAID-5 [In reply to]

On Mon, Jun 15, 2009 at 2:30 PM, <james [at] booths> wrote:
> Having just had a near-death experience with my non-RAID LVM system
> for Myth, I am about to convert everything to a RAID-5 setup (software
> RAID) with LVM on top.

Even though it's been said before on this thread, I'll say it again ...

Don't use RAID-5. The failure modes you get in RAID-5 coupled with the
disk health information available to the OS (i.e. basically none) mean
that you stand a reasonable chance of losing all your data
unexpectedly. RAID5 is a disk storage model based on a different
economic value for disks/controllers to how we operate today. Don't
use it :-)

You are storing archive data, so you don't need write performance,
just read performance. RAID1 is your simplest friend. Simplicity means
it's quick to recover when things go wrong. And they will :-)

You can have multiple disks in your RAID1 for redundancy, three would
be plenty. Two is probably acceptable, given the delivery times for
new disks these days. LVM on top gives the flexibility for growing &
importing volumes, but you know that.

> Before I go ahead does anyone have any
> recommendations on best choice of file system to use, given that it
> will be within LVM on RAID-5? I was going to go with XFS, but that
> cannot be shrunk, which (as I have found) can be very irritating when
> trying to reorganise your disks in an LVM.

Why shrink a filesystem? I guess if you haven't figured out how you
want to store things, perhaps ... but in general, filesystems only
grow :-)

Just stick with ext3 unless you really know the details of why you're
using something else (yes, not very sexy is it?). XFS should be good
by default for large objects, but you already don't like that ...

-jim

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jim at inode

Jun 15, 2009, 2:38 AM

Post #17 of 47 (3524 views)
Permalink

Re: File System for RAID-5 [In reply to]

On Mon, Jun 15, 2009 at 8:16 PM, Karl Leaning<mythtv [at] objectivity> wrote:
> Umm, no with raid 5, you lose a drive not the data. add a new drive
> "rebuild" the set and continue as normal...

Yes, true. Do you have a spare drive online? If you did, wouldn't you
be using it as a hot spare or part of the data set already?

If you lose a second drive while one drive is out of action ... you
lose data. Gone.

http://baarf.com/

RAID5 doesn't give enough protection for your data, especially given
the relative costs of media today. It has horrible failure modes,
especially given that we don't know about drive health (most drive try
self-healing without telling the OS that it's happening ... only
informsingthe OS when a fatal error has occured). For big systems,
RAID5 does not deliver decent performance (unlikely to be important
for MythTV usages)

> I have three 500GB drives in a raid-5 set.

Sounds like three nice 250GB RAID1 volumes to me :-)

-jim

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hads at nice

Jun 15, 2009, 2:49 AM

Post #18 of 47 (3526 views)
Permalink

Re: File System for RAID-5 [In reply to]

On Mon, 2009-06-15 at 21:38 +1200, Jim Cheetham wrote:
> If you lose a second drive while one drive is out of action ... you
> lose data. Gone.

Same as your two disk RAID1.

> RAID5 doesn't give enough protection for your data, especially given
> the relative costs of media today. It has horrible failure modes,
> especially given that we don't know about drive health (most drive try
> self-healing without telling the OS that it's happening ... only
> informsingthe OS when a fatal error has occured). For big systems,
> RAID5 does not deliver decent performance (unlikely to be important
> for MythTV usages)

Disks fail and notify how they do, no matter what arrangement they are
in.

RAID5 has enough performance for most things, is cheaper and is easy to
grow.

They both still have their uses.

hads
--
http://nicegear.co.nz
New Zealand's Open Source Hardware Supplier

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james at booths

Jun 15, 2009, 2:49 AM

Post #19 of 47 (3524 views)
Permalink

Re: File System for RAID-5 [In reply to]

On Monday 15 June 2009 21:29:58 Jim Cheetham wrote:
> On Mon, Jun 15, 2009 at 2:30 PM, <james [at] booths> wrote:
> > Having just had a near-death experience with my non-RAID LVM system
> > for Myth, I am about to convert everything to a RAID-5 setup (software
> > RAID) with LVM on top.
>
> Even though it's been said before on this thread, I'll say it again ...
>
> Don't use RAID-5. The failure modes you get in RAID-5 coupled with the
> disk health information available to the OS (i.e. basically none) mean
> that you stand a reasonable chance of losing all your data
> unexpectedly. RAID5 is a disk storage model based on a different
> economic value for disks/controllers to how we operate today. Don't
> use it :-)
>
> You are storing archive data, so you don't need write performance,
> just read performance. RAID1 is your simplest friend. Simplicity means
> it's quick to recover when things go wrong. And they will :-)
>
> You can have multiple disks in your RAID1 for redundancy, three would
> be plenty. Two is probably acceptable, given the delivery times for
> new disks these days. LVM on top gives the flexibility for growing &
> importing volumes, but you know that.
>
> > Before I go ahead does anyone have any
> > recommendations on best choice of file system to use, given that it
> > will be within LVM on RAID-5? I was going to go with XFS, but that
> > cannot be shrunk, which (as I have found) can be very irritating when
> > trying to reorganise your disks in an LVM.
>
> Why shrink a filesystem? I guess if you haven't figured out how you
> want to store things, perhaps ... but in general, filesystems only
> grow :-)
>
> Just stick with ext3 unless you really know the details of why you're
> using something else (yes, not very sexy is it?). XFS should be good
> by default for large objects, but you already don't like that ...
>
> -jim
>
> _______________________________________________
> mythtvnz mailing list
> mythtvnz [at] lists
> http://lists.ourshack.com/mailman/listinfo/mythtvnz
> Archives http://www.gossamer-threads.com/lists/mythtv/mythtvnz/

Well, I was orriginally considering RAID-1, the only issue being that I would
run out of SATA ports.

I need around 3TB of working storage, and have four 1.5TB drives. I also have
a DVD drive, giving a total of five drives. I have six SATA ports.

If I go RAID-1 then I get my 3TB, but cannot add in an extra pair of disks to
expand storage. With RAID-5 I can add in an extra 1.5TB drive. Yes, I could
add in another drive controller, but it all starts adding to the expense etc.

To be sure, I agree with you that RAID-1 is probably best, but while the
"economic model" may have changed, the storage requirements have gone up
dramatically as well.

I can see a seperate server with a bazillion TB of storage set up as RAID-10
in my future, but probably not just yet...

stevehodge at gmail

Jun 15, 2009, 3:01 AM

Post #20 of 47 (3522 views)
Permalink

Re: File System for RAID-5 [In reply to]

On Mon, Jun 15, 2009 at 9:49 PM, Hadley Rich <hads [at] nice> wrote:

> On Mon, 2009-06-15 at 21:38 +1200, Jim Cheetham wrote:
> > If you lose a second drive while one drive is out of action ... you
> > lose data. Gone.
>
> Same as your two disk RAID1.
>

Not quite. Lose a drive in a RAID5 and the rebuilt will mean accessing
every bit on every remaining drive. That can add enough stress to cause a
second drive to fail. Lose a drive in a RAID1 and at worst the load will
double, and then only if you keep using the filesystem.

Cheers,
Steve

stevehodge at gmail

Jun 15, 2009, 3:04 AM

Post #21 of 47 (3520 views)
Permalink

Re: File System for RAID-5 [In reply to]

On Mon, Jun 15, 2009 at 9:49 PM, James Booth <james [at] booths> wrote:

> Well, I was orriginally considering RAID-1, the only issue being that I
> would run out of SATA ports.
>

No spare PCI slots to add another controller?

Cheers,
Steve

stevehodge at gmail

Jun 15, 2009, 3:08 AM

Post #22 of 47 (3530 views)
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Re: File System for RAID-5 [In reply to]

On Mon, Jun 15, 2009 at 9:38 PM, Jim Cheetham <jim [at] inode> wrote:

> On Mon, Jun 15, 2009 at 8:16 PM, Karl Leaning<mythtv [at] objectivity>
> wrote:
> > I have three 500GB drives in a raid-5 set.
>
> Sounds like three nice 250GB RAID1 volumes to me :-)
>

If you're going to do that you could also consider a mdraid RAID10. That'd
give you one 750GB volume.

Cheers,
Steve

james at booths

Jun 15, 2009, 3:32 AM

Post #23 of 47 (3520 views)
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Re: File System for RAID-5 [In reply to]

On Monday 15 June 2009 22:04:07 Steve Hodge wrote:
> On Mon, Jun 15, 2009 at 9:49 PM, James Booth <james [at] booths> wrote:
> > Well, I was orriginally considering RAID-1, the only issue being that I
> > would run out of SATA ports.
>
> No spare PCI slots to add another controller?
>
> Cheers,
> Steve

One spare PCIe slot - but hoping to put another DVB card in that!

stevehodge at gmail

Jun 15, 2009, 3:32 AM

Post #24 of 47 (3528 views)
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Re: File System for RAID-5 [In reply to]

On Mon, Jun 15, 2009 at 10:01 PM, Steve Hodge <stevehodge [at] gmail> wrote:

> On Mon, Jun 15, 2009 at 9:49 PM, Hadley Rich <hads [at] nice> wrote:
>
>> On Mon, 2009-06-15 at 21:38 +1200, Jim Cheetham wrote:
>> > If you lose a second drive while one drive is out of action ... you
>> > lose data. Gone.
>>
>> Same as your two disk RAID1.
>>
>
> Not quite. Lose a drive in a RAID5 and the rebuilt will mean accessing
> every bit on every remaining drive. That can add enough stress to cause a
> second drive to fail. Lose a drive in a RAID1 and at worst the load will
> double, and then only if you keep using the filesystem.
>

I should have mentioned that eventually you'll have to read all the data off
the remaining drive of the mirror as well, my point was that in practice
RAID5 rebuilds have been more problematic.

g8ecj at gilks

Jun 15, 2009, 4:35 AM

Post #25 of 47 (3522 views)
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Re: File System for RAID-5 [In reply to]

> Quoting Robin Gilks <g8ecj [at] gilks>:
>
>>
>>> Having just had a near-death experience with my non-RAID LVM system
>>> for Myth, I am about to convert everything to a RAID-5 setup (software
>>> RAID) with LVM on top. Before I go ahead does anyone have any
>>> recommendations on best choice of file system to use, given that it
>>> will be within LVM on RAID-5? I was going to go with XFS, but that
>>> cannot be shrunk, which (as I have found) can be very irritating when
>>> trying to reorganise your disks in an LVM. I know there are a bunch of
>>> hot new file systems out now, but I? wary of trying something new in
>>> an a setup like this.
>>
>> Having just this last week built a replacement for my 6 year old server,
>> I've basically used the same scheme again.
>>
>> Huge raid5 array (the definition of huge is now very different to what
>> it
>> was 6 years ago!!), LVM2 over the top, recordings and video partitions
>> with jfs (large files but not many of them) and ext3 for all the other
>> partitions (email, music etc). The system disk is separate and gets
>> regular backups into an external device, most of the stuff on the raid
>> array is expendable but by using smartd and mdadm I get an email if
>> something starts to fail.
>>
>> Interesting that the new box is 10 times faster, has 5 times as much
>> disk,
>> 4 times as much ram and consumes less than half as much power...
>>
>>
>> --
>> Robin Gilks
>>
>>
> Hi Robin,
>
> This will be dedicated to Myth media files, so want something suited
> to large media files. Raid size is 3TB. Any particular reason you went
> for JFS over, say, XFS or others?

I choose jfs for the really large partitions because if there is the need
for a journal playback due to a back shutdown (kicking the plug out the
back was the last one!!) the rebuild is VERY much faster than with ext3.

I'm spinning 5TB in a raid5 (all the sata slots used now) but the old box
ran 4x200G and I had a failure with that. msadm sent me the email, I got
another drive, fdisk'ed it and a few hours later the array was rebuilt
with only about 10 minutes downtime (no lost recordings, good WAF) to
physically change the drive.

This time round I'm not bothering with the raid1 system disk, I'm just
doing regular backups to an external 1T drive - if that goes then new
disk, live CD, restore and off we go - which reminds me I must check that
I have a bootable CD with dar on it :-)

--
Robin Gilks

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