topic Re: Flash Cache 1TB upgrade CDOT FAS 8020 in ONTAP Discussions

Flash Cache 1TB upgrade CDOT FAS 8020

MK — Thu, 05 Jun 2025 05:16:42 GMT

We just dropped in two 1TB Flash Cache cards in to our CDOT 8.2.2 cluster this morning. The cards show up fine on each controller and it looks to be enabled but we are seeing a 0% hit percentage. What am I missing? I know the cards need to warm-up but the filer has been running for almost 6 hours and it is still at 0%...

ntap-cl01::> node run -node ntap-cl01-node01 -command options flexscale

flexscale.enable             on         (same value in local+partner recommended)
flexscale.lopri_blocks       on         (same value in local+partner recommended)
flexscale.normal_data_blocks on         (same value in local+partner recommended)
flexscale.pcs_high_res       off        (same value in local+partner recommended)
flexscale.pcs_size           0GB        (same value in local+partner recommended)
flexscale.readahead_blocks   off        (same value in local+partner recommended)
flexscale.rewarm             on         (same value in local+partner recommended)

ntap-cl01::> node run -node ntap-cl01-node01 -command stats show -p flexscale-access

Cache                                               Reads       Writes      Disk Reads
Usage    Hit   Meta   Miss Hit Evict Inval Insert Chain Blocks Chain Blocks Replaced
     %     /s     /s     /s   %    /s    /s     /s    /s     /s    /s     /s        /s
     0      0      0      0 100     0     0      2     0      0     0      0         0
     0      0      0      0 75     0     0      0     0      0     0      0         0
     0      0      0      0   0     0     0      3     0      0     0     12         0
     0      0      0      0 100     0     0      3     0      0     0      0         0

ntap-cl01::> node run -node ntap-cl01-node01 -command sysstat -x 1

CPU    NFS   CIFS   HTTP   Total     Net   kB/s    Disk   kB/s    Tape   kB/s Cache Cache    CP CP Disk   OTHER    FCP iSCSI     FCP   kB/s   iSCSI   kB/s
                                       in    out    read write    read write    age    hit time ty util                            in    out      in    out
23%   2403      0      0    2426    6829 167776 169400     24       0      0    42s    95%    0% -    81%      23      0      0       0      0       0      0
19%   3226      0      0    3226   13340 161935 166164      0       0      0     0s    96%    0% -    83%       0      0      0       0      0       0      0
36%   2388      0      0    2388    8945 138074 157052 42580       0      0     1     98%   41% Tf   84%       0      0      0       0      0       0      0
21%   2046      0      0    2046    5482 131457 167128 121088       0      0     0s    94% 100% :f   89%       0      0      0       0      0       0      0
32%   3232      0      0    3668   10094 202315 212984 115824       0      0     0s    94% 100% :f   82%     436      0      0       0      0       0      0
27%   3157      0      0    3173    7040 216534 220044 116224       0      0    55s    96% 100% :f   81%      16      0      0       0      0       0      0
28%   3746      0      0    3752    5845 245167 252088 125328       0      0     0s    96% 100% :f   82%       6      0      0       0      0       0      0
26%   3020      0      0    3020    5884 200317 205844 61052       0      0    57s    96%   66% :    85%       0      0      0       0      0       0      0
31%   2980      0      0    3001   13137 183224 186476      0       0      0     0s    95%    0% -    90%      21      0      0       0      0       0      0
25%   2905      0      0    3480   14162 163218 163084     24       0      0     0s    96%    0% -    84%     575      0      0       0      0       0      0
33%   2123      0      0    2308   13284 124891 156168 78696       0      0    59s    97%   46% Sf   95%     185      0      0       0      0       0      0
25%   3029      0      0    3035    5532 200730 203496 113984       0      0     0s    93% 100% :f   86%       6      0      0       0      0       0      0
29%   3385      0      0    3386    5786 217468 234453 130938       0      0     1     97%   99% Zs   83%       1      0      0       0      0       0      0
19%   2645      0      0    2645    9259 129553 140667 69682       0      0     0s    97%   36% :    92%       0      0      0       0      0       0      0

Re: Flash Cache 1TB upgrade CDOT FAS 8020

JSHACHER11 — Sat, 17 Jan 2015 19:33:54 GMT

- is that Flash Cache 2 (PAM2)? do you know the part number?

- why is 'lopri' on?

- is it showing in 'sysconfig -a'?

Re: Flash Cache 1TB upgrade CDOT FAS 8020

MK — Sat, 17 Jan 2015 19:39:48 GMT

It does show in sysconfig. I turned on lopri in an effort to try to get it to do at least something. I am banging my head against the wall. Am I just to impatient? Does it need a day before it starts to "learn" what to cache?

slot 2: Flash Cache 2 (1.0 TB)
                         State:     Enabled
                    Model Name:     X1974A-R6
                 Serial Number:     9436768886
                   Part Number:     111-00903
                Board Revision:     B0
                  FPGA Release:     3.3
                    FPGA Build:     201312121541
                        memory mapped I/O base 0x0000000044800000, size 0x80000

Re: Flash Cache 1TB upgrade CDOT FAS 8020

JSHACHER11 — Sat, 17 Jan 2015 20:05:35 GMT

- "Am I just to impatient?" - No. it should show inserts

- so you put one in each node and none works?

- is slot 1 available?

- would you be willing to do a takeover/giveback from both sides?

Re: Flash Cache 1TB upgrade CDOT FAS 8020

MK — Sat, 17 Jan 2015 20:36:39 GMT

There is a card in each node, and neither is working. I just performed a takeover/giveback and it still doesn't seem to help. Slot 1 is free. Does it require the card in slot 1?

ntap-cl01::> node run -node ntap-cl01-node02 -command stats show -p flexscale-access
Cache                                               Reads       Writes      Disk Reads
Usage    Hit   Meta   Miss Hit Evict Inval Insert Chain Blocks Chain Blocks Replaced
     %     /s     /s     /s   %    /s    /s     /s    /s     /s    /s     /s        /s
     0      0      0      0   0     0     0      0     0      0     0      0         0
     0      0      0      0   0     0     0      0     0      0     0      0         0
     0      0      0     61   0     0     0      0     0      0     0      0         0
     0      0      0    393   0     0     0      0     0      0     0      0         0
     0      0      0    428   0     0     0      0     0      0     0      0         0
     0      0      0    120   0     0     0      0     0      0     0      0         0
     0      0      0      0   0     0     0      0     0      0     0      0         0
     0      0      0      0   0     0     0      0     0      0     0      0         0
     0      0      0      0   0     0     0      0     0      0     0      0         0
     0      0      0      0   0     0     0      0     0      0     0      0         0
     0      0      0      0   0     0     0      0     0      0     0      0         0
     0      0      0      0   0     0     0      0     0      0     0      0         0
     0      0      0      0   0     0     0      0     0      0     0      0         0
     0      0      0      0   0     0     0      0     0      0     0      0         0
     0      0      0      0   0     0     0      0     0      0     0      0         0
     0      0      0      0   0     0     0      0     0      0     0      0         0
     0      0      0      0   0     0     0      0     0      0     0      0         0
     0      0      0      0   0     0     0      0     0      0     0      0         0
     0      0      0      0   0     0     0      0     0      0     0      0         0
     0      0      0      0   0     0     0      0     0      0     0      0         0

Re: Flash Cache 1TB upgrade CDOT FAS 8020

MK — Sun, 18 Jan 2015 02:25:06 GMT

Takeover/giveback had no change, still 0% usage. We added the same card to both nodes and both have the same issue. Slot 1 is empty, but the Hardware universe says slot 1 or 2 should be fine.

Re: Flash Cache 1TB upgrade CDOT FAS 8020

Uddhav — Sun, 18 Jan 2015 14:35:51 GMT

MK,

beside flexscale ON, what other things you do ?

I think your process has not completed yet.

Can you run down the birds eye view of the steps you did.

You have do something at aggr level. The IOps should skyrockt once you add those in aggr level.

System Manager tool - you can also use.

I am afraid, that just simply enabling that scale ON would do anything, you have to bring those inside your aggr level.

Re: Flash Cache 1TB upgrade CDOT FAS 8020

MK — Sun, 18 Jan 2015 16:28:32 GMT

I figured it out. Our data aggr's are hybrid with SSD Flashpools. Appraently, unbeknownst to me, you cannot use Flash Cache on Hybrid Flash Pool aggrs. If I am wrong please let me know? Otherwise it looks like I am returning the Flash Cache cards and adding a few more SSDs to the Flash Pool.

http://www.netapp.com/us/system/pdf-reader.aspx?m=tr-3832.pdf&cc=us

5.4 Flash Pool

Flash Cache and Flash Pool can be used together on one node (controller), within an HA pair, and within

a single clustered Data ONTAP cluster. Data from volumes that are provisioned in a Flash Pool

aggregate or an all-SSD aggregate is automatically excluded from being cached in Flash Cache. Data

from volumes provisioned in a Flash Pool aggregate uses Flash Pool cache, and data from volumes

provisioned in an SSD aggregate would not benefit from using Flash Cache.

Although Flash Cache and Flash Pool can be configured on the same node or within the same HA pair,

there are limits on the total cache that can be configured. The maximum cache sizes when using Flash

Cache and Flash Pool vary by controller model and Data ONTAP release; detailed information can be

found in the NetApp Hardware Universe, for customers who have NetApp Support site access.

Re: Flash Cache 1TB upgrade CDOT FAS 8020

JSHACHER11 — Sun, 18 Jan 2015 17:41:58 GMT

- all of your aggregates are FPs?

- FP is aggregate based cache while Flash Cache is system wide

- while both help with random reads, FP also helps with overwrites

- what was the need to provision Flash Cache given that you have FP?

- did you ever run PCS to predict the benefit?

Re: Flash Cache 1TB upgrade CDOT FAS 8020

MK — Sun, 18 Jan 2015 19:13:08 GMT

We ran wafl awa to determine that our FP was undersized. We had the option of obtaining Flash Cache cards, and I thought, without rearching enough, the the two combined would help. We only have one large data aggr per controller and they are both FP hybrids. It sounds like I should return the FC cards and expand the FP SSDs.

ntap-cl01::> system node run -node * "priv set advanced;wafl awa print"

2 entries were acted on.

Node: ntap-cl01-node01

Warning: These advanced commands are potentially dangerous; use

them only when directed to do so by NetApp

personnel.

### FP AWA Stats ###

Host ntap-cl01-node01 Memory 20166 MB

ONTAP Version NetApp Release 8.2.2 Cluster-Mode: Fri Aug 22 01:46:52 PDT 2014

AWA Version 1

Layout Version 1

CM Version 1

Basic Information

Aggregate aggr_data_node01

Current-time Wed Jan 14 09:08:03 EST 2015

Start-time Tue Jan 13 13:51:56 EST 2015

Total runtime (sec) 69368

Interval length (sec) 600

Total intervals 116

In-core Intervals 1024

Summary of the past 116 intervals

max

Read Throughput 300.948 MB/s

Write Throughput 28.250 MB/s

Cacheable Read (%) 65 %

Cacheable Write (%) 27 %

Max Projected Cache Size 1168 GiB

Projected Read Offload 16 %

Projected Write Offload 27 %

Summary Cache Hit Rate vs. Cache Size

Size 20% 40% 60% 80% 100%

Read Hit 9 10 12 13 16

Write Hit 23 24 24 24 27

The entire results and output of Automated Workload Analyzer (AWA) are

estimates. The format, syntax, CLI, results and output of AWA may

change in future Data ONTAP releases. AWA reports the projected cache

size in capacity. It does not make recommendations regarding the

number of data SSDs required. Please follow the guidelines for

configuring and deploying Flash Pool; that are provided in tools and

collateral documents. These include verifying the platform cache size

maximums and minimum number and maximum number of data SSDs.

### FP AWA Stats End ###

Node: ntap-cl01-node02

Warning: These advanced commands are potentially dangerous; use

them only when directed to do so by NetApp

personnel.

### FP AWA Stats ###

Host ntap-cl01-node02 Memory 20166 MB

ONTAP Version NetApp Release 8.2.2 Cluster-Mode: Fri Aug 22 01:46:52 PDT 2014

AWA Version 1

Layout Version 1

CM Version 1

Basic Information

Aggregate aggr_data_node02

Current-time Wed Jan 14 09:08:03 EST 2015

Start-time Tue Jan 13 13:51:47 EST 2015

Total runtime (sec) 69376

Interval length (sec) 600

Total intervals 116

In-core Intervals 1024

Summary of the past 116 intervals

max

Read Throughput 301.032 MB/s

Write Throughput 38.832 MB/s

Cacheable Read (%) 83 %

Cacheable Write (%) 34 %

Max Projected Cache Size 1423 GiB

Projected Read Offload 39 %

Projected Write Offload 35 %

Summary Cache Hit Rate vs. Cache Size

Size 20% 40% 60% 80% 100%

Read Hit 24 28 31 32 39

Write Hit 30 31 31 31 35