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HyperV 2008R2: hv_storvsc - write cache enabled in Linux guest RRS feed

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    dmesg output:

    [    8.080401] sd 0:0:0:0: [sda] Write cache: enabled, read cache: enabled, supports DPO and FUA

    Question: how safe is my (database) data in the case of a host machine crash or a VM crash?

    There is no battery-backed writecache installed in the host, just some cheap and slow SATA disks.

    Another curiosity occurs when running the fio iometer benchmark on the same machine: it gives me 5.000 to 6.000 I/O random access operations per second when using the para-virt hv_storvsc driver, but only the expected 200 I/O ops when using ata_piix via emulation.The kernel in question is version 3.2.11.

    There doesn't seem to be any way to disable the para-virt device's write-cache.

    Donnerstag, 15. März 2012 21:02
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