topic Re: using 100% of space?!?! but that is not true!!! in ONTAP Discussions

using 100% of space?!?! but that is not true!!!

InventuxBerlin — Tue, 17 Mar 2009 13:38:02 GMT

I have the error message:

Filer:
Version:
Status:

FAS1
Data ONTAP Release 7.2.5.1
/vol/ExchData is full (using or reserving 100% of space and 0% of inodes, using 57% of reserve).

That is not correctly!

On the volume is a LUN, only reserved 80GB. On the LUN is a Exchange data base. Snapshots take together only around the 10GB. Thus the 140GB cannot be full yet. Here a small overview of the Konfiguartion:

Aggregate                total         used         avail    capacity
aggr3                    908GB      845GB       62GB      93%
aggr3/.snapshot       47GB       11GB       36GB      24%

Filesystem                      total          used          avail capacity    Mounted on
/vol/ExchData/                140GB      140GB        0GB     100%      /vol/ExchData/
/vol/ExchData/.snapshot    60GB        5GB       54GB      10%       /vol/ExchData/.snapshot

Filesystem                      kbytes       used               avail       reserved       Mounted on
/vol/ExchData/                146800640 146800640          0      64863884      /vol/ExchData/
/vol/ExchData/.snapshot   62914560    5990628   56923932          0           /vol/ExchData/.snapshot

Name:	ExData
Type:	Flexible	Root Volume?	-
FlexClone ?	-	Containing Aggregate:	aggr0
Status:	online,raid4
Used Capacity:	140 GB	Space Guarantee	volume
% Used:	100%	Language:	de
Total Capacity:	140 GB	Total Size:	200 GB
Number of Files:	109	Max Directory Size:	8.96 MB
Max Files:	6.92 m

SNAP Mirror?	-	SNAP Directory?	enable
SNAP?	-	Resync SNAP Time:	60
SVO Enable?	-	SVO Checksum?	-
Allow SVO RMAN?	-	SVO Reject Errors?	-
Create Unicode?	enable	Convert Unicode?	enable
Minimal Read Ahead?	-	NV Fail?	-
Fractional Reserve :	100	Extent?	-
FS Size Fixed?	-	Update Access time?	enable
I2P?	enable	Ignore Inconsistent??	-

I hope you can me help, since I can make no Snapshots because of the error momentarily.

Thanks!!!!

Re: using 100% of space?!?! but that is not true!!!

BrendonHiggins — Tue, 17 Mar 2009 14:27:07 GMT

Welcome to the forum and it is a common question.

I think you have snap reserve set to 30% on your volume. Do can see this on the filer from cli with the command df -r -h ExchData.

Have a look at this document for a description of what is going on with LUNs and volumes.

http://media.netapp.com/documents/tr-3483.pdf

You have another problem in that your aggregate is 93% full and I think this will be performance issue sone, if it is not already an issue. I do not like to run above 85% on an aggregate.

Bren

Re: using 100% of space?!?! but that is not true!!!

BrendonHiggins — Tue, 17 Mar 2009 14:30:31 GMT

sorry forgot

snap reserve ExchData

will show the percentage

you can claim space bad with

snap reserve ExchData 20

This will set it to 20% and return space to the volume. As you have only used 10% of your reserve you will be OK to do this now and get snapshot working again.

Bren

Re: using 100% of space?!?! but that is not true!!!

InventuxBerlin — Tue, 17 Mar 2009 14:30:52 GMT

Because of the Snapshot mirror, can it be? Which it always actually needs the double used from which it?

Re: using 100% of space?!?! but that is not true!!!

InventuxBerlin — Tue, 17 Mar 2009 16:14:03 GMT

why should the performance sink starting from 85%?

Re: using 100% of space?!?! but that is not true!!!

BrendonHiggins — Tue, 17 Mar 2009 16:48:22 GMT

The system will be hunting for free blocks from the white list and will

not be able to stripe the write against the full raid group. You can

see this if you run a statit report. Look in the RAID section for

blocks written against the raid group size.

Re: using 100% of space?!?! but that is not true!!!

stuartwatkins — Wed, 18 Mar 2009 08:29:58 GMT

Yes Brendon is right and just to expand.

One of the great things that netapp does for you in terms of performance is when data is sent to it, the filer will hold it in cache until there is enough to do a full stripe write. This means it stripes the blocks of data across your raid group. As you can imagine this is much faster to read and write. The problem when you aggr becomes too full as yours is, is that there is not enough free space within the aggr to perform a full stripe write and therefore performance will really suffer.

Hope that makes sense

Re: using 100% of space?!?! but that is not true!!!

chriskranz — Wed, 18 Mar 2009 14:41:29 GMT

How big is the LUN in the volume?

It would seem to me that if you have ~60g reserved for the LUN, then your LUN is bigger than that (you mentioned 80g about something), so this would make perfect sense. Don't forget that as part of the snapshot process of a LUN, the filer will reserve 100% of the used space in the LUN for overwrites. So if you have written 60g to a 80g LUN, and you take a snapshot, you will be using 140g + whatever snapshot sizes, which is exactly the figures you have supplied.

I wrote a blog article that might help you understand this concept - http://communities.netapp.com/groups/chris-kranz-hardware-pro/blog/2009/03/05/fractional-reservation--lun-overwrite

As a side note, Brendon pointed out that you are reserving 30% for snapshots in this volume, but I am guessing from the volume name this is an Exchange LUN. If you are using SnapManager for Exchange and SnapDrive, it is recommended you reduce the snapshot reserve to 0% and use SnapDrive and SME to manage this for you.

Re: using 100% of space?!?! but that is not true!!!

D_BEREZENKO — Mon, 28 Oct 2013 12:19:06 GMT

Very similar situation:

vol create vol_orauivv_oradata1 aggr1 5120g

snap reserve vol_orauivv_oradata1 0

vol options vol_orauivv_oradata1 nosnap on

lun create -s 5099g -t linux /vol/vol_orauivv_oradata1/lun_orauivv_oradata1

After a wile it gets offline.

/vol/vol_orauivv_oradata1/lun_orauivv_oradata1 5.0t (5475009560576) (r/w, offline, mapped)

Sun Oct 27 00:43:00 EEST [netapp-s1:monitor.globalStatus.nonCritical:warning]: /vol/vol_oraoper_oradata2 is full (using or reserving 98% of space and 0% of inodes, using 98% of reserve). /vol/vol_oraoper_oraarc is full (using or reserving 100% of space and 0% of inodes, using 100% of reserve). /vol/vol_orauivv_oradata1 is full (using or reserving 100% of space and 0% of inodes, using 100% of reserve). /vol/vol_orauivv_orafb is full (using or reserving 100% of space and 0% of inodes, using 100% of reserve).

Sun Oct 27 01:00:00 EEST [netapp-s1:kern.uptime.filer:info]: 1:00am up 50 days, 9:28 0 NFS ops, 0 CIFS ops, 0 HTTP ops, 523927230 FCP ops, 0 iSCSI ops

What it can be?

Re: using 100% of space?!?! but that is not true!!!

aborzenkov — Mon, 28 Oct 2013 12:29:36 GMT

a) Snapshots

b) Intensive overwrite where it does not have time to free overwritten blocks fast enough.

c) Thin provisioned volumes so there is not enough space on aggregate

Re: using 100% of space?!?! but that is not true!!!

D_BEREZENKO — Mon, 28 Oct 2013 12:34:48 GMT

a) vol options vol_orauivv_oradata1 nosnap on

b) how to prevent this?

c) should I turn on snap reserv?

d) Can it be because of low quontity of inodes?

e) Can the deduplication make the impact?

Re: using 100% of space?!?! but that is not true!!!

aborzenkov — Mon, 28 Oct 2013 12:40:41 GMT

a) vol options vol_orauivv_oradata1 nosnap on

It does not mean there are no snapshots; it just stops Data ONTAP from creating scheduled snapshots.

b) how to prevent this?

You need to find out what is "this" first.

c) should I turn on snap reserv?

Makes no difference for LUN. You can also just create smaller LUN.

d) Can it be because of low quontity of inodes?

No.

e) Can the deduplication make the impact?

Yes. It seems to create snapshots internally.

Whatever you do, filling volume to 99,99% is asking for troubles.

Re: using 100% of space?!?! but that is not true!!!

D_BEREZENKO — Mon, 28 Oct 2013 12:51:14 GMT

>You need to find out what is "this" first.

>>b) how to prevent this?

>>>b) Intensive overwrite where it does not have time to free overwritten blocks fast enough.

Do I need just to reserve free space to prevent the Intensive overwrite? How much should I reserve, is it enough 2% on Vol (Best Practice) ?

In case of no snapshots were taken manually, moust propable situation is dedup, isn't it?

Re: using 100% of space?!?! but that is not true!!!

aborzenkov — Mon, 28 Oct 2013 12:55:25 GMT

The only way to prevent this is to leave enough headroom (free space) for your workload.

Re: using 100% of space?!?! but that is not true!!!

D_BEREZENKO — Mon, 28 Oct 2013 12:57:28 GMT

How much should I reserve, is it enough 4% on Vol (Best Practice) ?

Re: using 100% of space?!?! but that is not true!!!

aborzenkov — Mon, 28 Oct 2013 12:59:01 GMT

Best practice is 20%.

Re: using 100% of space?!?! but that is not true!!!

D_BEREZENKO — Mon, 28 Oct 2013 12:59:44 GMT

Can you please provide the name of the document, thanks!

Re: using 100% of space?!?! but that is not true!!!

D_BEREZENKO — Thu, 14 Nov 2013 06:57:15 GMT

I found only this:

215-07979_A0 Data ONTAP® 8.2 Storage Efficiency Management Guide For 7-Mode on a page 26

You can find there is 4% overhead:on volume.

"In a volume, deduplication metadata can occupy up to 4 percent of the total amount of data contained within the volume."

Re: using 100% of space?!?! but that is not true!!!

MattiaMigliorati — Mon, 20 Jul 2015 14:19:44 GMT

I cannot see your link, I've not understood why the occupied space is doubled..

Please share the link

Thank you

Mattia