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NTFS cluster blocking factor for MSDP database and MSDP data volumes?

Created: 15 Apr 2013 | 4 comments

Hi Forum - I've read elsewhere that is is recommended to format the NFTS volumes that will be used to house the MSDP database and MSDP data with a cluster size of 64 KB (i.e. 128 traditional 512 byte sectors).

However if if look at a slightly populated MSDP server, I see most files are less than 64 KB.

Does anyone have an opinion on this?

Top folders with files...

  F:\MSDP_Data\history\dataobjects            12

  F:\MSDP_Data\history\errors                 12

  F:\MSDP_Data\history\retention              12

  F:\MSDP_Data\history\segments               12

  F:\MSDP_Data\history\tasks                  12

  F:\MSDP_Data\history\tlogs                  12

  F:\MSDP_Data\log\pddb                       43

  F:\MSDP_Data\queue                          83

  F:\MSDP_Data\data                       26,205

  F:\MSDP_Data\processed                 103,610

Total = 130119

Table of file sizes...

  =           0         75

  >           0     29,708

  >           4     28,285

  >           8     22,436

  >          16     12,058

  >          32      4,585

  >          64     18,802

  >       1,024        879

  >      10,240        836

  >     102,400        220

  >     204,800     12,118

  >     409,600        108

  >   1,024,000          9

Total = 130119
 
 
 
Operating Systems:

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sdw305's picture

1) Ok. But why?

2) Does anyone know the typical I/O payload size caused by normal MSDP operation?

Area              IO         Avg Size

MSDP DB      Read     ? KB

MSDP DB      Write     ? KB

MSDP Data    Read     ? KB

MSDP Data    Write     ? KB

3) Has anyone ever benchmarked an N5220 appliance configured as an MSDP media server, to see whether it achieves the "minimum" of 200 MB/s read and write for 64 KB and 128 KB payload sizes?

Jaykullar's picture

You need to run SQL IQ or Symantec Camel Test to see the performance of your MSDP. Depends on how busy it is going to be, if its running for most of the time, and SLP'ing at the same time, and possibly rebasing, it is going to need to have high performance. This take into other factors in your contentrouter file, your array controllers, your SAN, your HBA settings on your storage server etc.

The minimum of 200mb/sec is advised, but obviously if your backing up a small amount then you may not need this type for performance.

sdw305's picture

1) But why is 64 KB recomended when most files on an MSDP DB volume and not empty but less than 4 KB ?  For an MSDP media server with:

C: O/S

D: Programs

E: MSDP DB            0.6 TB  used  of    2.0 TB available   1.4 TB free

F: MSDP Data        57.0 TB  used  of  60.0 TB available    3.0 TB free

...I see file counts/sizes:

FYI - On E:\ MSDP DB (database) - (no folders found with qty of files > 5000 files)

Table of file sizes...
  =           0        100
  >           0    189,455
  >           4          1
  >           8        159
  >          16        203
  >          32         41
  >          64         70
  >       1,024          1
  >      10,240         14
  >     102,400         10
  >     204,800          3
  >     409,600         17
  >   1,024,000        320
Total = 190394


...and ...on F:\ MSDP data volume:
Top folders with files...
  F:\MSDP_DATA\history\dataobjects           200
  F:\MSDP_DATA\history\errors                200
  F:\MSDP_DATA\history\retention             200
  F:\MSDP_DATA\history\segments              200
  F:\MSDP_DATA\history\tasks                 200
  F:\MSDP_DATA\history\tlogs                 200
  F:\MSDP_DATA\log\pddb                      211
  F:\MSDP_DATA\queue                      44,537
  F:\MSDP_DATA\processed                  73,733
  F:\MSDP_DATA\data                      491,821
Total = 611906

Table of file sizes...
  =           0        578
  >           0     15,672
  >           4     10,838
  >           8     26,701
  >          16     14,838
  >          32     12,106
  >          64    248,015
  >       1,024     36,656
  >      10,240     15,676
  >     102,400      6,434
  >     204,800    223,756
  >     409,600        522
  >   1,024,000        120
Total = 611912

So it appears to make sense to use an NTFS cluster factor of 64KB for the MSDP data volume, as most files are larger than 64 KB - and 30%+ of files are larger than 2 MB.

But it doesn't seem to make sense for the MSDP DB volumes where most (>98%) files are larger then 0 KB but less than 4KB in size.

2) I'll guess I'll have to try to determine average IO payload size from a few hours of PerfMon during a busy backup window.

3) Is anyone willing to benchtest their N5220 based MSDP media server (with local disk) using Camel ?  And share the results ?