04-15-2013 07:34 AM
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
04-16-2013 03:45 AM
I would stick with the notes for configuration and have them at 64K.
http://www.symantec.com/business/support/index?page=content&id=HOWTO61249
04-16-2013 04:27 AM
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?
04-16-2013 04:37 AM
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.
04-16-2013 05:54 AM
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 ?