<div dir="ltr">Hi Neha,<div><br></div><div style>LVM uses device mapper. Advantages of using device mapper is that you can stack different dm-targets on each other.</div><div style>I am really not aware of block device drivers.</div>
<div style><br></div><div style>May be Greg can help us understand the actual pros and cons.</div><div style><br></div><div style>Thanks,</div><div style>Gaurav </div></div><div class="gmail_extra"><br><br><div class="gmail_quote">
On Wed, May 1, 2013 at 9:45 PM, neha naik <span dir="ltr"><<a href="mailto:nehanaik27@gmail.com" target="_blank">nehanaik27@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Hi Gaurav,<br> I went through your blog and it is really informative. But after reading that i realized that i have a question:<br> If I want to write a block device driver which is going to sit on lvm (and do some functionality on top of it) then should i go for the block device driver api<br>
or write it as a device mapper target. What are the advantages/disadvantages of both the approaches.<br><br>Regards,<br>Neha<div class="HOEnZb"><div class="h5"><br><br><div class="gmail_quote">On Tue, Apr 30, 2013 at 4:24 AM, Gaurav Mahajan <span dir="ltr"><<a href="mailto:gauravmahajan2007@gmail.com" target="_blank">gauravmahajan2007@gmail.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr">Hi Amit,<div><br></div><div>I had compiled some notes on my blog.</div><div>Here are some links on writing your own device mapper target.<br>
</div><div><a href="http://techgmm.blogspot.in/p/writing-your-own-device-mapper-target.html" target="_blank">http://techgmm.blogspot.in/p/writing-your-own-device-mapper-target.html</a><br>
</div><div><br></div><div>Concept of device mapper target.</div><div><a href="http://techgmm.blogspot.in/p/device-mapper-layer-explored-every.html" target="_blank">http://techgmm.blogspot.in/p/device-mapper-layer-explored-every.html</a><br>
</div><div><br></div><div>Thanks,</div><div>Gaurav.</div></div><div><div><div class="gmail_extra"><br><br><div class="gmail_quote">On Tue, Apr 30, 2013 at 5:05 AM, Anatol Pomozov <span dir="ltr"><<a href="mailto:anatol.pomozov@gmail.com" target="_blank">anatol.pomozov@gmail.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Hi<br>
<div><br>
On Mon, Apr 29, 2013 at 9:51 AM, amit mehta <<a href="mailto:gmate.amit@gmail.com" target="_blank">gmate.amit@gmail.com</a>> wrote:<br>
> On Sun, Apr 28, 2013 at 5:24 PM, Greg Freemyer <<a href="mailto:greg.freemyer@gmail.com" target="_blank">greg.freemyer@gmail.com</a>> wrote:<br>
>> A nice diagram of the overall storage subsystem is at <a href="http://www.thomas-krenn.com/en/oss/linux-io-stack-diagram.html" target="_blank">http://www.thomas-krenn.com/en/oss/linux-io-stack-diagram.html</a><br>
>><br>
>> Dm is just a single block in it, but it can help to see where it fits in overall.<br>
>><br>
>> Btw: that diagram doesn't show the legacy ata driver that creates /dev/hdx style devices. Has that been dropped while I wasn't paying attention? I haven't used it in years, but I thought it was still used on embedded systems.<br>
>><br>
><br>
> Thank you for sharing the link, but I'm looking for more<br>
> detailed information on I/O stack in Linux, dm-mapper and<br>
> multipath in particular.<br>
<br>
</div>Some docs about multipath can be found here<br>
<br>
<a href="http://www.sourceware.org/lvm2/wiki/MultipathUsageGuide" target="_blank">http://www.sourceware.org/lvm2/wiki/MultipathUsageGuide</a><br>
<a href="http://christophe.varoqui.free.fr/refbook.html" target="_blank">http://christophe.varoqui.free.fr/refbook.html</a><br>
<br>
The userspace part for tools is here<br>
<a href="http://sourceware.org/lvm2/" target="_blank">http://sourceware.org/lvm2/</a><br>
<div><div><br>
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