* Re: btrfs raid1 balance slow
2020-01-20 22:08 btrfs raid1 balance slow kjansen387
@ 2020-01-20 22:13 ` Hugo Mills
2020-01-20 23:59 ` Qu Wenruo
2020-01-21 9:51 ` kjansen387
2 siblings, 0 replies; 5+ messages in thread
From: Hugo Mills @ 2020-01-20 22:13 UTC (permalink / raw)
To: kjansen387; +Cc: linux-btrfs
On Mon, Jan 20, 2020 at 11:08:40PM +0100, kjansen387 wrote:
> I had a btrfs raid1 with 2 4TB SATA 5400RPM disks . Regular disk I/O is
> about 2MB/sec per drive, ~40IOPS, mostly write. I had ~150GB free and added
> one 2 TB disk and started the balance:
>
> btrfs device add -f /dev/sdb /export
> btrfs filesystem balance /export
>
> It's now running for 24 hours, 70% remaining:
>
> # btrfs balance status -v /export
> Balance on '/export' is running
> 1057 out of about 3561 chunks balanced (1058 considered), 70% left
> Dumping filters: flags 0x7, state 0x1, force is off
> DATA (flags 0x0): balancing
> METADATA (flags 0x0): balancing
> SYSTEM (flags 0x0): balancing
>
> I have searched for similar cases, but, I do not have quotas enabled, I do
> not have compression enabled, and my CPU supports sse4_2 . CPU (i7-8700K) is
> doing fine, 80% idle (average over all threads).
Do you have lots of snapshots? It can take a lot of time on some of
the metadata chunks if there's lots of shared extents.
> Is this normal ? I have to repeat this process 2 times (adding more 2TB
> disks), any way I can make it faster ?
Cancel the current balance, add the remaining disks, and then
balance only once you've added them all.
Hugo.
--
Hugo Mills | If it's December 1941 in Casablanca, what time is it
hugo@... carfax.org.uk | in New York?
http://carfax.org.uk/ |
PGP: E2AB1DE4 | Rick Blaine, Casablanca
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: btrfs raid1 balance slow
2020-01-20 22:08 btrfs raid1 balance slow kjansen387
2020-01-20 22:13 ` Hugo Mills
@ 2020-01-20 23:59 ` Qu Wenruo
2020-01-21 9:51 ` kjansen387
2 siblings, 0 replies; 5+ messages in thread
From: Qu Wenruo @ 2020-01-20 23:59 UTC (permalink / raw)
To: kjansen387, linux-btrfs
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On 2020/1/21 上午6:08, kjansen387 wrote:
> Hello,
>
> I had a btrfs raid1 with 2 4TB SATA 5400RPM disks . Regular disk I/O is
> about 2MB/sec per drive, ~40IOPS, mostly write. I had ~150GB free and
> added one 2 TB disk and started the balance:
>
> btrfs device add -f /dev/sdb /export
> btrfs filesystem balance /export
>
> It's now running for 24 hours, 70% remaining:
>
> # btrfs balance status -v /export
> Balance on '/export' is running
> 1057 out of about 3561 chunks balanced (1058 considered), 70% left
> Dumping filters: flags 0x7, state 0x1, force is off
> DATA (flags 0x0): balancing
> METADATA (flags 0x0): balancing
> SYSTEM (flags 0x0): balancing
>
> I have searched for similar cases, but, I do not have quotas enabled, I
> do not have compression enabled, and my CPU supports sse4_2 . CPU
> (i7-8700K) is doing fine, 80% idle (average over all threads).
Are you using qgroup?
If so, that would be the cause.
Please use kernel newer than v5.2, which contains the optimization.
>
> Is this normal ? I have to repeat this process 2 times (adding more 2TB
> disks), any way I can make it faster ?
Just as Hugo said, cancel the current one, add all device, then rebalance.
Thanks,
Qu
>
> Thanks!
> Klaas
>
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^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: btrfs raid1 balance slow
2020-01-20 22:08 btrfs raid1 balance slow kjansen387
2020-01-20 22:13 ` Hugo Mills
2020-01-20 23:59 ` Qu Wenruo
@ 2020-01-21 9:51 ` kjansen387
2020-01-22 8:18 ` kjansen387
2 siblings, 1 reply; 5+ messages in thread
From: kjansen387 @ 2020-01-21 9:51 UTC (permalink / raw)
To: linux-btrfs
Forgot to mention; I'm running kernel 5.4.10-200.fc31.x86_64 .
Op 20-Jan-20 om 23:08 schreef kjansen387:
> Hello,
>
> I had a btrfs raid1 with 2 4TB SATA 5400RPM disks . Regular disk I/O is
> about 2MB/sec per drive, ~40IOPS, mostly write. I had ~150GB free and
> added one 2 TB disk and started the balance:
>
> btrfs device add -f /dev/sdb /export
> btrfs filesystem balance /export
>
> It's now running for 24 hours, 70% remaining:
>
> # btrfs balance status -v /export
> Balance on '/export' is running
> 1057 out of about 3561 chunks balanced (1058 considered), 70% left
> Dumping filters: flags 0x7, state 0x1, force is off
> DATA (flags 0x0): balancing
> METADATA (flags 0x0): balancing
> SYSTEM (flags 0x0): balancing
>
> I have searched for similar cases, but, I do not have quotas enabled, I
> do not have compression enabled, and my CPU supports sse4_2 . CPU
> (i7-8700K) is doing fine, 80% idle (average over all threads).
>
> Is this normal ? I have to repeat this process 2 times (adding more 2TB
> disks), any way I can make it faster ?
>
> Thanks!
> Klaas
>
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: btrfs raid1 balance slow
2020-01-21 9:51 ` kjansen387
@ 2020-01-22 8:18 ` kjansen387
0 siblings, 0 replies; 5+ messages in thread
From: kjansen387 @ 2020-01-22 8:18 UTC (permalink / raw)
To: linux-btrfs
Hmm, for some reason, I did not get the mail from Hugo and Qu (had too
look it up in the archive). I think there is a delay when subscribing to
the email list.
> Do you have lots of snapshots? It can take a lot of time on some of
the metadata chunks if there's lots of shared extents.
No, I do not have any snapshots. Never made one - just got started with
btrfs.
# btrfs subvolume show /export | grep Snap
Snapshot(s):
> Are you using qgroup?
No, quotas are disabled:
# btrfs qgroup show /export
ERROR: can't list qgroups: quotas not enabled
>Please use kernel newer than v5.2, which contains the optimization.
I'm running 5.4.10-200.fc31.x86_64, that should be good
> Just as Hugo said, cancel the current one, add all device, then
rebalance.
Yes, that would be the best. I'm moving data however.. Expand btrfs >
move the content of a 2TB disk > use that disk to expand btrfs > move
the content of a 2TB disk etc. When this balance is done I'll move 2TB,
find a temp drive to store the other 2TB and add the remaining 2 drives
in 1 go.
I'm not in a hurry.. just wondering if this is normal. As I had 2x4TB
with 150GB free and am adding 1x2TB (~1800GB, ~900 after raid1) I would
expect that I will end up with 150+900=1050 GB free (usable), spread
like (approx.):
4TB disk 1: 420GB (previously: 75GB)
4TB disk 2: 420GB (previously: 75GB)
2TB disk: 210GB
Thinking very simplisticly -and that's probably where I'm wrong, just
wondering if it's a factor 8 wrong- this would mean 420-75 = 345GB read
from each 4TB disks and written to the new 2TB disk. At a rate of 20MB/s
(pretty conservative, but I do have a little bit of load) this should
take like 10 hours. It will, however, at this rate, take approx. 82
hours. Even if all data needs to be read (does it? ~3500GB net) it
should only take ~50 hours..
Klaas
^ permalink raw reply [flat|nested] 5+ messages in thread