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Deciphering DRAM and Flash sizes & upgrading
Kaminsky
Member Posts: 1,235
in CCNA & CCENT
Searched the forum and couldn't find it so thought I would post.
Calculating DRAM (holds ios in memory + config + variables + working memory)
Show version:
….. lines omitted
cisco 3725 (R7000) processor (revision 0.1) with 252928K/9216K bytes of memory.
….. lines omitted
Which Suggests:
252928K/9216K = (free)/(used) = 252928K + 9216K = 262144 / 1024 = 256MB DRAM
and
Calculating flash size (where images are stored)
Show flash:
….. lines omitted
[25634836 bytes used, 6477804 available, 32112640 total]
….. lines omitted
Which suggests:
25634836 bytes used = 25634836 / 1024 / 1024 = 24.447 MB used
6477804 available = 6477804 / 1024 / 1024 = 6.178 MB available
32112640 total = 32112640 / 1024 / 1024 = 30.625 MB total flash size or 32MB
When buying from ebay, you should always ask for a show version and show flash to see exactly how much you are going to need to pay out on top to upgrade to fit the IOS image you want. Your aiming for about 12.4T or above. On some devices, you can't upgrade.
Google search> “Upgrading system memory in Cisco <router/switch model> site:cisco.com” will give you the information on how to physically upgrade including pictures how to do it, how much you can upgrade and what memory models you can upgrade with.
You can also use show version to check out exactly what version of IOS you will be getting.
Look up the IOS on Cisco.com to see what version and, more importantly, what type of ios it is. Types can be a basic ip, advanced ip, security, enterprise, etc.
With a little bit of homework, you can pick up some unsuspecting gems quite cheaply. It can also stop you getting saddled with some lame ducks.
Calculating DRAM (holds ios in memory + config + variables + working memory)
Show version:
….. lines omitted
cisco 3725 (R7000) processor (revision 0.1) with 252928K/9216K bytes of memory.
….. lines omitted
Which Suggests:
252928K/9216K = (free)/(used) = 252928K + 9216K = 262144 / 1024 = 256MB DRAM
and
Calculating flash size (where images are stored)
Show flash:
….. lines omitted
[25634836 bytes used, 6477804 available, 32112640 total]
….. lines omitted
Which suggests:
25634836 bytes used = 25634836 / 1024 / 1024 = 24.447 MB used
6477804 available = 6477804 / 1024 / 1024 = 6.178 MB available
32112640 total = 32112640 / 1024 / 1024 = 30.625 MB total flash size or 32MB
When buying from ebay, you should always ask for a show version and show flash to see exactly how much you are going to need to pay out on top to upgrade to fit the IOS image you want. Your aiming for about 12.4T or above. On some devices, you can't upgrade.
Google search> “Upgrading system memory in Cisco <router/switch model> site:cisco.com” will give you the information on how to physically upgrade including pictures how to do it, how much you can upgrade and what memory models you can upgrade with.
You can also use show version to check out exactly what version of IOS you will be getting.
Look up the IOS on Cisco.com to see what version and, more importantly, what type of ios it is. Types can be a basic ip, advanced ip, security, enterprise, etc.
With a little bit of homework, you can pick up some unsuspecting gems quite cheaply. It can also stop you getting saddled with some lame ducks.
Kam.
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laidbackfreak
Member Posts: 991
Good post
It's one of the things I recall learning way back and at the time I didn't really understand the reasons behind it. It's nice to see it laid out clear and simple to use and understand.if I say something that can be taken one of two ways and one of them offends, I usually mean the other one :-)