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Determining Machine Class and Disk Usage

Determining Machine Class and Disk Usage

This section shows you the process of determining:

Required disk space is primarily dependent on the following factors:

The following section contains more information:

Using the Worksheets Effectively

The calculations in the worksheets assume the following:


Note If the number of devices that a TrafficDirector host is polling for statistical data is greater than five, Cisco Systems recommends that this machine be dedicated to logging.

Selecting a Suitable Machine to Support Logging

To select a suitable machine to support the logging operations you want to configure, follow these steps. This information will also help you determine if you need additional systems as well.

Step 1 The number of devices you want the TrafficDirector application to poll directly impacts your choice of hardware configuration.

Fill out Form 1 (Table D-1) according to the following information:


Note If the total number of devices from Worksheet 1 is greater than five, Cisco Systems recommends that the machine be dedicated for logging.
Table D-1: Worksheet 1---Number of Devices
Device Type Number of Devices

Agent

Switch

Frame Relay

Total


Step 2 Based on the total number of devices you entered in Worksheet 1 (Table D-1), use the information in Table D-2 to determine the recommended machine configuration.


Table D-2: Recommended Machine Configuration
The Configuration of the Machine Should Be:
For This
Operating
System...
And This
Many Devices
to be Polled...
CPU Class Main
Memory
Swap
Space
Number of
Processes
Temporary
Disk Space

UNIX

1-25

Class 1

256 MB

256 MB

60

120 MB

UNIX

26-50

Class 2

512 MB

512 MB

110

240 MB

Windows

1-25

Class 1

128 MB

256 MB

60

120 MB

Windows

26-50

Class 2

256 MB

512 MB

110

240 MB

Table D-3 lists the Class 1 and Class 2 recommended models.


Table D-3: Class 1 and Class 2 Recommended Models
CPU Class Hardware Platform Recommended Model

Class 1

Sun SPARC

Sparc 20, Ultra 1

Class 1

HP 9000 Series 700 or 800

730/100

Class 1

IBM RS/6000

397/43P model 140

Class 1

Windows NT

Intel Pentium 166

Class 2

Sun SPARC

Ultra 2

Class 2

HP 9000 Series 700 or 800
(Limited to 50 processes.)

HP 777

Class 2

IBM RS/6000

397/43P model 140

Class 2

Windows NT

Intel Pentium Pro

Step 3 Fill out Worksheet 2 (Table D-4) according to the frequency that you want to log Stats, Host and Conversations data for each device type. For example, if you configure logging for Agent Statistics every 5 minutes, enter 5 minutes for Agent/Statistics. Similarly, if you are logging Agent TopN Hosts every 15 minutes, enter 15 minutes in the Agents/TopN Hosts field, and so on.


Table D-4: Worksheet 2---Logging Frequency
Device Type Statistics TopN Hosts All Hosts TopN Conv All Conv

Agent

Switch

Frame Relay

Frame Relay PVCs

Agent

Step 4 Use Table D-5 to correlate the values you specified in Worksheet 2 to the number of intervals per day. For example, if you specified five minutes, the equivalent interval per day value is 288.


Table D-5: Interval Table
Time Intervals (I) Per Day

5 min

288

15 min

96

30 min

48

1 hr

24

2 hr

12

4 hr

6

8 hr

3

24 hr

1

Step 5 In Worksheet 3 (Table D-6), enter the intervals per day for each category of each device type.


Table D-6: Worksheet 3---Intervals Per Day
Device Type Statistics TopN Hosts All
Hosts
TopN
Conv
All
Conv

Agent

Switch

N/A

N/A

N/A

N/A

Frame Relay

Frame Relay PVCs

N/A

N/A


Note 
You should include all Full Duplex agents in the Frame Relay agent total. You should include WAN and Fast Ethernet FX interfaces in the Frame Relay total in Step 6, but exclude them from the Agent total.

Step 6 Calculate the total number of monitored interfaces (RMON agents) for each device type, as follows:

Step 7 Apply the formulas specified in Table D-7 and Table D-8 for each Device-Statistic combination.

Step 8 Enter the results of each calculation under the appropriate heading.

Note the following abbreviations:

I

Intervals per day specified in Form

R

250 bytes (size of database record)

NH

TopN value for Hosts (default is 50; the actual value for your location is in the SQLDB.dvp file within the USR directory)

NC

TopN value for Conversations (default is 50; the actual value for your location is in the SQLDB.dvp file within the USR directory)

D

Number of Domains (increment by 1 if one of those domains is RMON)

P

Number of active switch ports (from Step 6)

PVC

Number of active PVCs (from Step 6)


Table D-7: Formulas to Calculate Daily Disk Usage per Device-Statistic Combination
Device
Type
Statistics TopN Hosts All Hosts TopN Conv All Conv

Agent

I * R * D

I * R * D * NH

I * R * 10000

I * R * D * NC

I * R * 10000

Switch

I * R *2 * P

Does not apply

Does not apply

Does not apply

Does not apply

Frame
Relay

I * R * D * 3

I * R * D * NH

I * R * 10000

I * R * D * NC

I * R * 10000

PVCs

I * R * D * 3 * PVC

I * R * D * NH * PVC

I * R * 10000 * PVC

I * R * D * NC * PVC

I * R * 10000 * PVC


Table D-8: Daily Disk Usage Requirements per Device-Statistic Combination
Device
Type
Statistic TopN
Hosts
All
Hosts
TopN Conv All
Conv
Total Disk Usage Per Device

Agent

(A1)

(A2)

(A3)

(A4)

(A5)

Sum of A1 through A5 = ___MB

Switch

(S1)

N/A

N/A

N/A

N/A

Sum of S1 through S5 = ___MB

Frame
Relay

(FR1)

(FR2)

(FR3)

(FR4)

(FR5)

Sum of FR1 through FR5 = ___MB

PVCs

(P1)

(P2)

N/A

(P3)

N/A

Sum of P1 through P5 = ___MB

Step 9 Enter values in Worksheet 4 (Table D-9) to calculate Total Disk Usage per Day.


Table D-9: Worksheet 4---Total Disk Usage Per Day
Device
Type
Total Disk Usage
Per Device
(From Table D-8)
X Total Number of Monitored Interfaces
for Agents/Frame Relay
Agents (From Step 6)
= Total Disk Usage
Per Day

Agent

Switch

Frame
Relay

(A)

Frame
Relay PVC

1

Step 10 Using the Configure Rollup application in the TrafficDirector Admin window, you can configure aging (in days) for both the detail and the summary tables. The aging value is the actual number of days the data will remain in the database before the dbrolld utility begins to delete the oldest rows first to make room for new information. Enter the number of days you are Aging the Detail database tables: ________days.

Step 11 Use the following formula to calculate long-term disk usage:

      Total Disk Usage for all Devices * Aging = Total Long-Term Disk Usage Requirement
      


Table D-10: Worksheet 5---Results

Recommended Machine Class

Disk Space Requirements

Step 12 Do the following to reduce disk space requirements:

Sample Forms

The sample information provided in Tables D-11 through D-15 illustrate how to use the Trend Reporter calculation forms.

The following agents are monitored in the example:

Consider the following:


Table D-11: Form 1---Number of Devices
Device Type Number of Devices

Agent

4

Switch

1

Frame Relay

1

Total

6


Table D-12: Form 2---Logging Frequency
Device Type Statistics TopN Hosts All Hosts TopN Conv All Conv

Agent

5 min

15 min

---

15 min

---

Switch

15 min

---

---

---

Frame Relay

15 min

15 min

---

15 min

---

Frame Relay PVCs

15 min

4 hr

---

4 hr

---


Table D-13: Form 3---Intervals Per Day
Device Type Statistics TopN Hosts All
Hosts
TopN
Conv
All
Conv

Agent

288

96

---

96

---

Switch

96

---

---

---

---

Frame Relay

96

96

---

96

---

Frame Relay PVCs

96

6

---

6

---

The total number of monitored interfaces (RMON agents) for each device type, as follows:


Table D-14: Daily Disk Usage Requirements per Device-Statistic Combination
Device
Type
Statistic TopN
Hosts
All
Hosts
TopN Conv All
Conv
Total Disk Usage
Per Device (Sum of)

Agent

(A1)
1.44 Mb

(A2)
12 Mb

(A3)

(A4)
12 Mb

(A5)

A1 through A5 = 25.44 Mb

Switch

(S1)
4.80 Mb

N/A

---

---

---

S1 through S5 = 4.80 Mb

Frame
Relay

(FR1)
1.44 Mb

(FR2)
12 Mb

(FR3)

(FR4)
12 Mb

(FR5)

FR1 through FR5 = 25.44 Mb

PVCs

(P1)
36 Mb

(P2)
18.7 Mb

---

(P3)
18.7 Mb

---

P1 through P5 = 73.4 Mb


Table D-15: Form 4---Total Disk Usage Per Day
Device
Type
Total Disk Usage
Per Device
(From Table D-8)
Times Total No. of Monitored Interfaces
for Agents/Frame Relay
Agents (From Step 6)
Equals Total Disk Usage
Per Day

Agent

25.44 Mb

4

101.76 Mb

Switch

4.80 Mb

1

4.80 Mb

Frame
Relay

25.44 Mb

1

25.44 Mb

Frame
Relay PVC

73.40 Mb

1

73.40 Mb

Total Disk Usage For All Devices Per Day

205.40 Mb

The number of days for Aging the Detail database tables: 31 days

Long-term disk usage:

205.4 Mb * 31 days = 6.367.4 Mb

Recommended Machine Class---Class 1

Disk Space Requirement---6,367.4 Mb


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Posted: Fri Mar 31 09:14:24 PST 2000
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