Which memories hold running configuration of the router?

Dynamic random-access memory (DRAM) contains two types of memory:

• Primary, main, or processor memory, which is reserved for the CPU to execute Cisco IOS software and to hold the running configuration and routing tables.

• Shared, packet, or I/O memory, which buffers data transmitted or received by the router’s network interfaces.

On the Cisco 3600 series routers, you can use the memory-sizeiomem command to configure the proportion of DRAM devoted to main memory and to shared memory.

DRAM often comes on dual in-line memory modules (DIMMs).

Erasable programmable read-only memory (EPROM) is often referred to simply as ROM. On Cisco devices, the EPROM often contains the following:

• ROM Monitor software, which provides a user interface for troubleshooting the ROM.

• The boot loader/helper software, which helps the router boot when it cannot find a valid Cisco IOS image in Flash memory.

Non-volatile random-access-memory (NVRAM) stores the following information:

• Startup configuration file for every platform except Class A Flash file system platforms (for Class A Flash file system platforms, the location of the startup configuration depends on the CONFIG_FILE Environment Variable).

• The software configuration register, which is used to determine which image to use when booting the router.

Flash memory stores the Cisco IOS software image. On most platforms, it can store boot-images and/or configuration files.

Depending on the hardware platform, Flash memory might be available as EPROM, single in-line memory modules (SIMMs), dual in-line memory modules (DIMMs), or Flash memory cards. Check the appropriate hardware installation and maintenance guide for information about types of Flash memory available on a specific platform.

Depending on the platform, Flash memory is available in the following forms:

• Internal Flash memory

  • Internal Flash memory often contains the system image.
  • Some platforms have two or more banks of Flash memory on one in-line memory module (in other words, on one SIMM). If the SIMM has two banks, it is sometimes referred to as dual-bank Flash memory . The banks can be partitioned into separate logical devices. See the “Partitioning Flash Memory ” section for information about how to partition Flash memory.
• Bootflash

  • Bootflash often contains the boot image.
  • Bootflash sometimes contains the ROM Monitor.

• Flash memory PC cards or PCMCIA cards

A Flash memory card that is inserted in to a Personal Computer Memory Card International Association (PCMCIA) slot. This card is used to store system images, boot images, and configuration files.

Note

Because some platforms, such as the Cisco 3600 series and Cisco the 7000 family, can boot images and load configuration files from several locations, these systems use special ROM monitor environment variables to specify the location and filename of images and configuration files that the router is to use for various functions.

Ma ny Cisco routers load the system image from flash storage into RAM in order to run the Cisco IOS. However, some platforms, such as the Cisco 1600 Series and Cisco 2500 Series, execute the Cisco IOS operation system directly from Flash memory. These platforms are run-from-Flash memory systems.

If you want to partition Flash memory, you must use a relocatable image. Relocatable images can be run from any location in Flash and can download images to any location. If you are upgrading from a nonrelocatable image to a relocatable image, you must erase Flash memory during the download so that the image is downloaded as the first file in Flash memory. All images for run-from-Flash platforms from Cisco IOS Release 11.0 and later are relocatable. See the “ Image Naming Conventions ” section in the “Loading and Maintaining System Images” chapter to determine if your images are run-from-Flash images or are relocatable.

Flash memory provides write protection against accidental erasing or reprogramming. Some platforms have a write-protect jumper which can be removed to prevent reprogramming of Flash memory. You must install the jumper when programming is required. Some platforms have write protect switched on Flash memory cards that you can use to protect data. You must set the switch to unprotected to write data to the Flash memory card. Refer to your hardware documentation for information on security jumpers and write protect switches.

Note	The internal Flash and Flash memory cards of a system cannot be used as a contiguous bank of Flash memory.

To partition Flash memory, you must have at least two banks of Flash memory; a bank is a set of 4 chips. This requirement includes systems that support a single SIMM that has two banks of Flash memory. The minimum partition size is the size of a bank.

Note	The CiscoFlash MIB variables support partitioned Flash.

Partitioning Flash memory provides the following benefits:

• For any system, partitioning--rather than having one logical Flash memory device--provides a cleaner way of managing different files in Flash memory, especially if the Flash memory size is large.

• For systems that execute code out of Flash memory, partitioning allows you to download a new image into the file system in one Flash memory bank while an image is being executed from the file system in the other bank. The download is simple and causes no network disruption or downtime. After the download is complete, you can switch over to the new image at a convenient time.

• One system can hold two different images, one image acting as a backup for the other. Therefore, if a downloaded image fails to boot for some reason, the earlier running, good image is still available. Each bank is treated as a separate device.

Flash load helper is a software option that enables you to upgrade system s oftware on run-from-Flash systems that have a single bank of Flash memory. It is a lower-cost software upgrade solution than dual-bank Flash, which requires two banks of Flash memory on one SIMM. Flash load helper is only available on run-from-Flash platforms, such as the Cisco 2500 series, Cisco 3000, and Cisco 5200.

You might use Flash load helper rather than partitioning Flash into two banks for one of the following reasons:

• If you want to download a new file into the same bank from which the current system image is executing.

• If you want to download a file that is larger than the size of a bank, and hence want to switch to a single-bank mode.

• If you have only one single-bank Flash SIMM installed. In this case, Flash load helper is the best option for upgrading your software.

See the “Downloading Files Using the Flash Load Helper ” section for information about using Flash load helper.

Flash load helper performs the following functions:

• Confirms access to the specified source file on the specified server before erasing Flash memory and reloading to the ROM image for the actual upgrade.

• Warns you if the image being downloaded is not appropriate for the system.

• Prevents reloads to the ROM image for a Flash upgrade if the system is not set up for automatic booting and the user is not on the console terminal. In the event of a catastrophic failure during the upgrade, Flash load helper can bring up the boot ROM image as a last resort rather than forcing the system to wait at the ROM monitor prompt for input from the console terminal.

• Retries Flash downloads automatically up to six times. The retry sequence is as follows:

  • First try
  • Immediate retry
  • Retry after 30 seconds
  • Reload ROM image and retry
  • Immediate retry
  • Retry after 30 seconds

• Allows you to save any configuration changes made before you exit out of the system image.

• Notifies users logged in to the system of the impending switch to the boot ROM image so that they do not lose their connections unexpectedly.

• Logs console output during the Flash load helper operation into a buffer that is preserved through system reloads. You can retrieve the buffer contents from a running image. The output is useful when console access is unavailable or a failure occurs in the download operation.

Flash load helper can also be used on systems with multiple banks of Flash memory that support Flash memory partitioning. Flash load helper enables you to download a new file into the same partition from which the system is executing an image.

For information about how to partition multiple banks of Flash memory so your system can hold two different images, see the “Partitioning Flash Memory ” section.

1.    enable


2.    show flash-filesystem :[all | chips |filesys]


3.    show flash-filesystem :[partitionnumber ][all | chips | detailed | err | summary]


4.    show flash-filesystem :


5.    show file systems

Router> enable

Router# show flash: chips

Router# show slot0: detailed

Router# show slot1:

Router# show file system

To partition Flash memory, complete the tasks in this section.

Note

This task will succeed only if the system has at least two banks of Flash and the partitioning does not cause an existing file in Flash memory to be split across the partitions. For all platforms except the Cisco 1600 series and Cisco 3600 series, Flash memory can only be partitioned into two partitions. For the Cisco 1600 series and Cisco 3600 series, the number of partitions that you can create in a Flash memory device equals the number of banks in the device. Enter the showflash-filesystem:all command to view the number of banks on the Flash memory device. The number of partition size entries you set must be equal to the number of specified partitions. For example, the partitionslot0:288 command configures two partitions to be 8 MB in size each. The first 8 corresponds to the first partition; the second 8 corresponds to the second partition.

1.    enable


2.    configure terminal


3.    partition flash partitions [size1 size2 ]


4.    partition flash-filesystem : [number-of-partitions ] [partition-size ]

Router> enable

Router# configure terminal

Router(config)# partition flash 2 4 4 

Router(config)# Router(config)# partition slot0: 2 8 8 

1.    enable


2.    Do one of the following:

• copy tftp: flash:
• copy rcp: flash:
• copy ftp: flash:

Router> enable

Router# copy tftp flash:

Troubleshooting

ERR: Config register boot bits set for manual booting

Examples

Router#
 copy tftp: flash:
*************************** NOTICE *******************************
Flash load helper v1.0
This process will accept the TFTP copy options and then terminate
the current system image to use the ROM based image for the copy. 
Router functionality will not be available during that time. If 
you are logged in via telnet, this connection will terminate. Users 
with console access can see the results of the copy operation.
******************************************************************
There are active users logged into the system. 
Proceed? [confirm] y
System flash directory:
File Length  Name/status
1    2251320 abc/igs-kf.914
[2251384 bytes used, 1942920 available, 4194304 total]
Address or name of remote host [255.255.255.255]? 
172.16.1.111
Source file name? 
abc/igs-kf.914
Destination file name [default = source name]?
 
Accessing file ‘abc/igs-kf.914’ on 172.16.1.111....
Loading from 172.16.13.111:
Erase flash device before writing? [confirm] n
File ‘abc/igs-kf.914’ already exists; it will be invalidated!
Invalidate existing copy of ‘abc/igs-kf.914’ in flash memory? [confirm] y
Copy ‘abc/igs-kf.914’ from TFTP server
as ‘abc/igs-kf.914’ into Flash WITHOUT erase? y
%SYS-5-RELOAD: Reload requested
%
FLH: rxboot/igs-kf.914r from 172.16.1.111 to flash...

System configuration has been modified. Save? [confirm]

**System going down for Flash upgrade**

Troubleshooting Tips

• Restrictions
• Flash Memory Formatting Process
• Recovering from Locked Blocks

Flash Memory Formatting Process

Caution

The following formatting procedure erases all information in Flash memory. To prevent the loss of important data, proceed carefully.

Use the following procedure to format Flash memory. If you are formatting internal Flash memory, such as bootflash, you can skip the first step. If you are formatting a Flash memory card, complete both steps:

SUMMARY STEPS

1.    Insert the new Flash memory card into a PCMCIA slot. Refer to instructions on maintaining the router and replacing PCMCIA cards in your router’s hardware documentation for instructions on performing this step.

2.    Enter the format [spare spare-number ] device1: [[device2:][monlib-filename ]]command to format Flash memory.

DETAILED STEPS

---

Step 1	Insert the new Flash memory card into a PCMCIA slot. Refer to instructions on maintaining the router and replacing PCMCIA cards in your router’s hardware documentation for instructions on performing this step.
Step 2	Enter the format [spare spare-number ] device1: [[device2:][monlib-filename ]]command to format Flash memory.

---

Examples

The following example shows the format command that formats a Flash memory card inserted in slot 0.

Router# format slot0:
Running config file on this device, proceed? [confirm]y
All sectors will be erased, proceed? [confirm]y
Enter volume id (up to 31 characters): 
Formatting sector 1 (erasing)
Format device slot0 completed

Recovering from Locked Blocks

Note

To recover from locked blocks, reformat the Flash memory card. A locked block of Flash memory occurs when power is lost or a Flash memory card is unplugged during a write or erase operation. When a block of Flash memory is locked, it cannot be written to or erased, and the operation will consistently fail at a particular block location. The only way to recover from locked blocks is by reformatting the Flash memory card with the format command. Caution Formatting a Flash memory card to recover from locked blocks will cause existing data to be lost. To view your current mix of processor and I/O memory and reassign memory distribution accordingly, complete the tasks in this section:

SUMMARY STEPS

1.    enable


2.    show version


3.    show memory


4.    configure terminal


5.    memory-size iomem I/O-memory-percentage


6.    exit


7.    copy system:running-config nvram:startup-config


8.    reload

DETAILED STEPS

	Command or Action	Purpose
Step 1	enable Example: Router> enable	Enables privileged EXEC mode. Enter your password if prompted.
Step 2	show version Example: Router# show version	Displays the total amount of memory loaded on the router.
Step 3	show memory Example: Router# show memory	Displays the amount of free memory. Note    The Free(b) column in the show memory command’s output shows how much I/O memory is available.
Step 4	configure terminal Example: Router# configure terminal	Enters global configuration mode.
Step 5	memory-size iomem I/O-memory-percentage Example: Router(config)# memory-size iomem 50	Allocates processor memory and I/O memory. Note    The default is 40 percent for I/O memory and 60 percent for processor memory
Step 6	exit Example: Router(config)# exit	Exits global configuration mode.
Step 7	copy system:running-config nvram:startup-config Example: Router# copy system:running-config nvram:startup-config	Saves the configuration to NVRAM.
Step 8	reload Example: Router# reload	Reloads the router to run the new image.

Troubleshooting Tips

Valid I/O memory percentage values are 10, 15, 20, 25, 30, 40 (the default), and 50. I/O memory size is the specified percentage of total memory size, rounded down to the nearest multiple of 1 MB. A minimum of 4 MB of memory is required for I/O memory. The remaining memory is processor memory.

The memory-sizeiomem command does not take effect until you save it to NVRAM using the copysystem:running-confignvram:startup-config EXEC command and reload the router. However, when you enter the command, the software checks whether the new memory distribution leaves enough processor memory for the currently running Cisco IOS image. If not, the following message appears:

Warning: Attempting a memory partition that does not provid
e enough Processor memory for the current image.If you write memory now, this version of so
ftware may not be able to run.

When you enter the reload command to run a new image, the software calculates the new processor and I/O memory split. If there is not enough processor memory, it automatically reduces I/O memory to an alternative setting to load the image. If there is still not enough processor memory for the image to run, then you do not have enough DRAM.

Examples

The following example allocates 40 percent of DRAM to I/O memory and the remaining 60 percent to processor memory. The example views the current allocation of memory, changes the allocation, saves the allocation, and reloads the router so the changes can take effect. In the showmemorycommand output, the Free(b) column shows how much I/O memory is available:

Router# show memory
               Head   Total(b)    Used(b)    Free(b)  Lowest(b) Largest(b)
Processor  60913730    3066064     970420    2095644    2090736    2090892
      I/O    C00000    4194304    1382712    2811592    2811592    2805492
--More-- 
Router# configure terminal
Enter configuration commands, one per line.  End with CNTL/Z.
Router(config)# memory-size iomem 40
Router(config)# exit
Router#
Router# copy system:running-config nvram:startup-config
Building configuration...
[OK]
Router# reload
rommon > boot
program load complete, entry point: 0x80008000, size: 0x32ea24
Self decompressing the image : ###################################################################################################################################################################################################################################################### [OK]

Configuring and Verifying Memory Scan on the Cisco 7500 Series

Router# show memory scan
Memory scan is on.
No parity error has been detected.

Router# show memory scan
Memory scan is off
No parity error has been detected.

Router# show memory scan
Memory scan is on.
Total Parity Errors 1.
Address BlockPtr BlckSize Disposit   Region Timestamp
6115ABCD 60D5D090   9517A4  Scrubed    Local 16:57:09 UTC Thu Mar 18