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Ring Buffer Configuration Guide: Difference between revisions
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The '''Webshark''' and the '''pcap''' extraction works with historic dates as in the screenshot here on the right. This dialogue is shown by using the '''pcap''' button in the Allegro User Interface. The Allegro Network Multimeter will search for all packets in the '''ring buffer''' if they match the criteria and extracts the packets. | The '''Webshark''' and the '''pcap''' extraction works with historic dates as in the screenshot here on the right. This dialogue is shown by using the '''pcap''' button in the Allegro User Interface. The Allegro Network Multimeter will search for all packets in the '''ring buffer''' if they match the criteria and extracts the packets. | ||
If there is no '''ring buffer''' configured, the Allegro allows a '''pcap''' extraction of live traffic only. | If there is no '''ring buffer''' configured, the Allegro Network Multimeter allows a '''pcap''' extraction of live traffic only. | ||
== Different '''ring buffer''' modes == | == Different '''ring buffer''' modes == | ||
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[[File:Settings button.png|border|100px]] | [[File:Settings button.png|border|100px]] | ||
Here you can increase the number of cluster ring buffers. We will continue this tutorial with 2 ring buffers to show the full flexibility of the Allegro. Please note that you need to restart the processing when you change the parameter. This can be done at '''Settings''' → '''Administration''' → '''Restart processing'''. | Here you can increase the number of cluster ring buffers. We will continue this tutorial with 2 ring buffers to show the full flexibility of the Allegro Network Multimeter. Please note that you need to restart the processing when you change the parameter. This can be done at '''Settings''' → '''Administration''' → '''Restart processing'''. | ||
To enable the cluster ring buffer mode, please check at '''Generic''' → '''ring buffer''', if the tab ''cluster configuration'' is selected or not. If it is not, selected, delete the non-cluster ring buffer with: | To enable the cluster ring buffer mode, please check at '''Generic''' → '''ring buffer''', if the tab ''cluster configuration'' is selected or not. If it is not, selected, delete the non-cluster ring buffer with: | ||
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Note that one disk can have '''one''' shared ring buffer or be part of '''one''' cluster ring buffer. Hard disk drives have a high constant write rate when only one write is active. | Note that one disk can have '''one''' shared ring buffer or be part of '''one''' cluster ring buffer. Hard disk drives have a high constant write rate when only one write is active. | ||
The Allegro Network Multimeter has a ''write first'' policy on the ring buffer devices. The Allegro prioritizes writes over reads for storage. A pcap read can be very slow when there is a high write rate to the ring buffer. | The Allegro Network Multimeter has a ''write first'' policy on the ring buffer devices. The Allegro Network Multimeter prioritizes writes over reads for storage. A pcap read can be very slow when there is a high write rate to the ring buffer. | ||
=== Concurrent '''ring buffer''' and live '''pcap''' recording === | === Concurrent '''ring buffer''' and live '''pcap''' recording === | ||
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'''''DISCLAIMER''' Whenever possible, use a direct-connected exclusive external storage device via USB. The Allegro Network Multimeter can control the USB channel far better than an iSCSI channel due to exclusivity.'' | '''''DISCLAIMER''' Whenever possible, use a direct-connected exclusive external storage device via USB. The Allegro Network Multimeter can control the USB channel far better than an iSCSI channel due to exclusivity.'' | ||
The iSCSI ring buffer feature allows you to mount an iSCSI volume via the management interface. Allegro recommends to use this feature only for capture rates up to 1GBit/s. The iSCSI controller will have an exclusive low-latency connection to the Allegro Network Multimeter and the rate shall be exclusive to the Allegro Network Multimeter. Also, the management traffic between the Allegro and the iSCSI rate will not be monitored by the Allegro to prevent a write loop. | The iSCSI ring buffer feature allows you to mount an iSCSI volume via the management interface. Allegro recommends to use this feature only for capture rates up to 1GBit/s. The iSCSI controller will have an exclusive low-latency connection to the Allegro Network Multimeter and the rate shall be exclusive to the Allegro Network Multimeter. Also, the management traffic between the Allegro Network Multimeter and the iSCSI rate will not be monitored by the Allegro Network Multimeter to prevent a write loop. | ||
If the rate is non-exclusive, other reads or writes will heavily reduce the constant write rate. Note that the iSCSI connection is not encrypted. | If the rate is non-exclusive, other reads or writes will heavily reduce the constant write rate. Note that the iSCSI connection is not encrypted. | ||
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The Allegro Network Multimeter uses an '''AES256 LUKS encryption container''' for encrypted single shared ring buffers. You can connect and mount the encrypted disk with many Linux Distributions. It will ask for your password to mount the container. | The Allegro Network Multimeter uses an '''AES256 LUKS encryption container''' for encrypted single shared ring buffers. You can connect and mount the encrypted disk with many Linux Distributions. It will ask for your password to mount the container. | ||
The Allegro uses hardware encryption if available. The Allegro 200 does not have HW encryption support and can encrypt up to 400MBit/s in software. All other Allegro devices can encrypt with 2GB/s by using the built-in hardware encryption. | The Allegro Network Multimeter uses hardware encryption if available. The Allegro 200 does not have HW encryption support and can encrypt up to 400MBit/s in software. All other Allegro devices can encrypt with 2GB/s by using the built-in hardware encryption. | ||
The Allegro does ''not'' store the password of the encrypted device on the disk. you need to re-enter the password if you unmount, reboot or power-off the Allegro Network Multimeter. | The Allegro Network Multimeter does ''not'' store the password of the encrypted device on the disk. you need to re-enter the password if you unmount, reboot or power-off the Allegro Network Multimeter. | ||
The encryption is not available for the cluster ring buffer. | The encryption is not available for the cluster ring buffer. | ||