I didn't do the math, but just an idea:
ONTAP calculates an average file size of 32K to determine the number of inodes per volume. Every inode takes 192 Bytes from the INODEFILE. So, if you take 2TB / 32KB * 192B = 12GB... (actually I *did* do the math right now, I was curious...)
It seems this is enforced on *newer* aggregates... According to KB https://kb.netapp.com/support/index?page=content&id=3011432 you can't go below the VolSize/32K limit.
How about provisioning the volumes small (and thin) and letting them *AutoGrow* to 2TB? That way, they're not using up space (not even for inodes), yet are able to contain up to 2TB...
Just my 2c
Sebastian
On 12/10/2015 8:43 AM, Mike Thompson wrote:
sample vol and aggr details below
can't upgrade, not on support, we have about 1PB in production across two clusters. I am seeing this effect on both clusters, but not on all filers, which is strange.
if I move vols between affected and unaffected filers/aggrs, the allocated vs used normalizes for the volumes on the unaffected node, then re-inflate when moved back to the original node/aggr
Volume Allocated Used vol created on problem aggr v164402 11932348KB 1924KB after move to unaffected aggr v164402 2872KB 2872KB after move back to orig aggr v164402 12005552KB 75284KB
resized to 1TB, moved to another aggr, and back to orig aggr
v164402 6003080KB 37972KBit appears to be related to the size of the volume. we thin-provision all volumes by setting them to a large size and set space guarantee to none.
vols sized at 2TB end up being allocated 12GB of space when created. vols sized to 1TB end up with 6GB allocated when created, even though they are completely empty.
what's strange is this is happening on some filers/aggregates but not others.
these clusters originated running Ontap GX, and then were upgraded to Ontap8 c-mode some time ago.
the aggregates that seem to be experiencing this allocation 'inflation' seem to be those that were created after the cluster was upgraded to Ontap8.
the aggregates that were originally created as GX aggrs, have identically matching 'allocated' and 'used' values in 'aggr show_space'
for example:
recently built aggregate under Ontap8:
Aggregate Allocated Used Avail Total space 18526684036KB 13662472732KB 1233809368KB <- massive difference!
aggregate originated under Ontap GX:
Aggregate Allocated Used Avail Total space 32035928920KB 32035928920KB 1404570796KB <- identical, which is what i would expect
maybe this allocation scheme changed at an aggregate level under Ontap 8? perhaps it's expected behavior?
things do seem to normalize as the volumes begin to fill up though, so I believe that this space is not truly gone permanently, but it certainly appears to be not available for use, since tons of space is allocated to volumes that have very little data in them, and we have a LOT of volumes in these clusters.
it's definitely making it look like we are missing a substantial percentage of our disk space, when trying to reconcile the sum of data used when tallying up volume size, and comparing it to the aggregate used/remaining sizes.
example volume and affected aggregate details:
bc-gx-4b::*> vol show v164346 -instance (volume show)
Virtual Server Name: bc Volume Name: v164346 Aggregate Name: gx4b_1 Volume Size: 2TB Name Ordinal: base Volume Data Set ID: 4041125 Volume Master Data Set ID: 2151509138 Volume State: online Volume Type: RW Volume Style: flex Volume Ownership: cluster Export Policy: default User ID: jobsys Group ID: cgi Security Style: unix Unix Permissions: ---rwxr-x--x Junction Path: /bc/shows/ID2/DFO/0820 Junction Path Source: RW_volume Junction Active: true Parent Volume: v164232 Virtual Server Root Volume: false Comment: Available Size: 1.15TB Total Size: 2TB Used Size: 146.7MB Used Percentage: 42% Autosize Enabled (for flexvols only): false Maximum Autosize (for flexvols only): 2.40TB Autosize Increment (for flexvols only): 102.4GB Total Files (for user-visible data): 31876689 Files Used (for user-visible data): 132 Maximum Directory Size: 100MB Space Guarantee Style: none Space Guarantee In Effect: true Minimum Read Ahead: false Access Time Update Enabled: true Snapshot Directory Access Enabled: true Percent of Space Reserved for Snapshots: 0% Used Percent of Snapshot Reserve: 0% Snapshot Policy: daily Creation Time: Tue Dec 08 11:22:582015 Language: C Striped Data Volume Count: - Striped Data Volume Stripe Width: 0.00B Current Striping Epoch: - One data-volume per member aggregate: - Concurrency Level: - Optimization Policy: - Clone Volume: false Anti-Virus On-Access Policy: default UUID of the volume: 17fa4c6d-9de1-11e5-a888-123478563412 Striped Volume Format: - Load Sharing Source Volume: - Move Target Volume: false Maximum Write Alloc Blocks: 0 Inconsistency in the file system: false
bc-gx-4b::*> aggr show -aggregate far4a_1 gx1a_1 gx1a_2 gx1b_1 gx2a_1 gx2b_1 gx3a_1 gx4b_1 near1b_1 near3b_1 root_1a root_1b root_2a root_2b root_3a root_3b root_4a root_4b slow2a_1 systems bc-gx-4b::*> aggr show -aggregate gx4b_1
Aggregate: gx4b_1 UUID:c624f85e-96d3-11e3-a6ce-00a0980bb25a Size: 18.40TB Used Size: 17.25TB Used Percentage: 94% Available Size: 1.15TB State: online Nodes: bc-gx-4b Number Of Disks: 63 Disks: bc-gx-4b:0a.64, bc-gx-4b:0e.80, ... bc-gx-4b:0a.45 Number Of Volumes: 411 Plexes: /gx4b_1/plex0(online) RAID Groups: /gx4b_1/plex0/rg0, /gx4b_1/plex0/rg1, /gx4b_1/plex0/rg2 Raid Type: raid_dp Max RAID Size: 21 RAID Status: raid_dp Checksum Enabled: true Checksum Status: active Checksum Style: block Inconsistent: false Ignore Inconsistent: off Block Checksum Protection: on Zoned Checksum Protection: - Automatic Snapshot Deletion: on Enable Thorough Scrub: off Volume Style: flex Volume Types: flex Has Mroot Volume: false Has Partner Node Mroot Volume: false Is root: false Wafliron Status: - Percent Blocks Scanned: - Last Start Error Number: - Last Start Error Info: - Aggregate Type: aggr Number of Quiesced Volumes: - Number of Volumes not Online: - Number of LS Mirror Destination Volumes: - Number of DP Mirror Destination Volumes: - Number of Move Mirror Destination Volumes: - Number of DP qtree Mirror Destination Volumes: - HA Policy: sfo Block Type: 64-bit
On Wed, Dec 9, 2015 at 12:50 PM, John Stoffel <john@stoffel.org mailto:john@stoffel.org> wrote:
Can you post the details of one of these volumes? And of the aggregate you have them in? It smells like there's some sort of minimum volume size setting somewhere. Or maybe there's an aggregate level snapshot sitting around? Can you upgrade? You're in cluster mode, so hopefully it shoudln't be too hard to move to 8.1, then 8.2 and onto 8.3, since there's lots of nice bug fixes.
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