[SPDK] Re: Unable to run OCF bdev, bdev not attached

Yes I've read this article. I'm just curious that is there any possibility
I can directly use the filesystem(ext4) above OS, while entire filesystem
(on HDD) is accelerated by SPDK + OCF transparently.

I know SPDK has its BlobFS, however by far it only supports append-only
write. It seems to me that using the OS filesystem is a more practical way.

Cao, Gang <gang.cao(a)intel.com> 于2020年8月28日周五 下午3:43写道：

> >
> > Are you using the OCF bdev for the FIO?
> >
>
> No I'm not, the FIO command was directly run on /dev/sdk1. I suppose it's
> a aio bdev so I can read/write it directly with the OS?
>
> [Gang]: Looks like this is the problem. You will need to configure the
> SPDK OCF bdev for the FIO and the FIO is based on SPDK bdev layer. Please
> follow below link:
>
> https://mp.weixin.qq.com/s?__biz=MzI3NDA4ODY4MA==&mid=2653335424&idx=1&sn=0f4dfc6c884cea4780c016902dab59e8&chksm=f0cb5807c7bcd111a815ded1bab1dd8260167c59eab71ba729e27ec1f76b266e23b5f1a08bf2&token=1477511457&lang=zh_CN#rd
>
> For the SPDK code, you still could use you current code, this is more
> about reference of the OCF and FIO configuration.
>
> -----Original Message-----
> From: Bob Chen <a175818323(a)gmail.com>
> Sent: Friday, August 28, 2020 15:38
> To: Storage Performance Development Kit <spdk(a)lists.01.org>
> Subject: [SPDK] Re: Unable to run OCF bdev, bdev not attached
>
> >
> >
> > What kind of workloads from FIO?
>
>
> 4KB sequential write or randwrite
>
>
> > And what's the capacity of the NVMe SSD as Cache device for the Core
> > device (HDD).
> >
>
> 7TB SSD, 3.7TB HDD, 64KB OCF cache line
>
>
> >
> > Are you using the OCF bdev for the FIO?
> >
>
> No I'm not, the FIO command was directly run on /dev/sdk1. I suppose it's
> a aio bdev so I can read/write it directly with the OS?
>
>
> >
> > If there is detailed configuration of FIO and OCF Bdev, that will be
> > helpful.
> >
> > Thanks,
> > Gang
> >
> > -----Original Message-----
> > From: Bob Chen <a175818323(a)gmail.com>
> > Sent: Friday, August 28, 2020 15:20
> > To: Storage Performance Development Kit <spdk(a)lists.01.org>
> > Subject: [SPDK] Re: Unable to run OCF bdev, bdev not attached
> >
> > Hi, folks
> >
> > I solved this issue by myself. It's because the latest SPDK needs 2MB
> > hugepages while the spdk_tgt app applies 1GB by default.
> >
> > Then I began to run some fio commands on the core device (/dev/sdk1),
> > but surprisingly found that there was NO performance improvement at all.
> >
> > Using SPDK + OCF to accelerate a HDD by an NVMe SSD, is this a correct
> > scenario?
> >
> > <a175818323(a)gmail.com> 于2020年8月27日周四 下午5:58写道：
> >
> > > ./rpc.py bdev_nvme_attach_controller -b Nvme0 -t PCIe -a
> > > 0000:3b:00.0 ./rpc.py bdev_aio_create /dev/sdk1 Aio0 512 ./rpc.py
> > > bdev_ocf_create
> > > Cache0 wb Nvme0n1 Aio0 --cache-line-size 64
> > >
> > >
> > > Inserting cache Cache0
> > > Cache0: Metadata initialized
> > > Cache0: Successfully added
> > > Cache0: Cache mode : wb
> > > Cache0: Attaching cache device failed
> > > vbdev_ocf.c:1016:start_cache_cmpl: *ERROR*: Error -1000013 during
> > > start cache Cache0, starting rollback
> > > Cache0: Cannot flush cache - cache device is detached
> > > Cache0: Cache Cache0 successfully stopped
> > >
> > >
> > > Looks like the cache/core device is not attached, what else should I
> > > do to make it work?
> > >
> > > P.S. I have run Open-CAS-Linux successfully on this machine, so the
> > > cas_cache and cas_cache ko are currently loaded. casctl and casadm
> > > tools exist as well.
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